Navy M1 Garand - History Summaries

I read this interesting email and wanted to share with the group. I will post pics of my Navy M1 later in the week.

From: bartbob@aol.com (Bartbob)
Newsgroups: rec.guns
Subject: Re: Garand Navy 308 Question
Date: 10 Mar 1999 10:22:13 -0500

I'm really surprized at all the incorrect information posted regarding these US
Navy M1 Garands in 7.62mm NATO. If anybody chooses to talk with anyone
directly involved in the USN's NATO Garand program in the middle 1960s, here's
what they will learn.

In the early 1960s, the USN Small Arms Marksmanship Unit in San Diego (located
at what used to be Camp Elliot south of Miramar NAS) wanted to do two things.
One was to upgrade all their rifles used for training recruits at USNTC San
Diego to use the 7.62mm NATO round. The other was to upgrade all their match
grade service rifles to the same cartridge. Virtually all of this was
spearheaded by Charles Frazier; a retired Navy chief petty officer who went to
work as a civil service employee of the US Navy. Charlie ran the Match
Conditioning Unit where work on both rifles and pistols was as good as it got.

Someone suggested a chamber insert. Several were made and the project came up
with what seemed to work well. But after a long period of testing and use,
and several of these inserts comming out with the empty case, this idea was
quickly abandoned. There were fewer problems by just using a 7.62mm NATO round
in an unmodified .30-06 service chamber.

The US Navy contacted Springfield Armory in Mass. to make a batch of barrels on
the same machines used to make them for the 30 caliber Garands. The only
differences were the bore was rifled 1:12 (30 caliber barrels were 1:10) and
chamber them for the 7.62mm NATO round. All these barrels were broach cut
rifled. They were all stamped "7.62 NATO) on their right side just in front of
the tenon shoulder and this is visible when the op rod is pulled back. They
were also date stamped in 1964 or 1965; the year they were made. And they were
all chrome-moly material; none were made in stainless steel.

At the USN Small Arms Match Conditioning Unit at the same place as the Training
Unit, all these M1 7.62mm barrels were measured with a Sheffield air gage for
groove diameter uniformity. Those with the smallest groove diameters with most
uniformity were set aside for use in the match grade M1s. About 40% of about
3000 or so barrels met this criteria. All the rest were set aside for use in
standard training rifles. The last two numbers of the groove diameter was
scribed on the barrel. If the groove diameter was .3078 inch, "78" was put on
the barrel. Groove diameters ranged from .3077- to .3082-inch. Those at or
under .3079-inch were considered match-grade. Most interesting was how uniform
in groove diameters these broach-cut barrels were.

As the M1s were first being converted, it was found that in test firing, the
gas supplied to the op rod to function the rifle was not quite enough with the
standard 30 caliber barrels's gas port diameter. These holes had to be opened
up a few thousandths of an inch. It was a standard operating procedure that
when a new 7.62mm M1 barrel was pulled from the box to go in a rifle, the gas
port was drilled out. The second thing that was done was to knurl the barrel
where the lower band went so it would be a tighter fit.

I've watched the shop crew rebarrel many 30 caliber M1s to service and match
grade 7.62mm NATO Garands. It doesn't take very long to drill and knurl the
barrel, strip the barrel group of an M1, put the barreled action in the
barreling machine, replace the barrel, then put everything back together. The
big difference is what they did to the match grade ones in fitting all the
parts and using the select-grade barrels for them. Especially in how the gas
cylinder and op rod were fitted as well as epoxy bedding the receiver with the
barrel set in the right thickness of spacer on the stock's front end to get the
right amount of pull-down pressure when the lower band was on the ferrule.

They didn't stamp the receiver with any new markings. Nor did they mark
anything else special with either the service or match grade M1s they
converted. But there was one exception. Anybody who's actually used on of the
match grade ones has noted the color mark on the gas cylinder lock ring; they
were color coded as to how they clocked up tight on the barrel against the gas
cylinder.

Each grade, service or match, was given a Mark and Mod designation; I don't
remember what they were.

Some interesting things about these M1s. Four of them were used in the late
1960s by a USN team to beat the best bolt gun team in the USA at a long range
match. Match-grade M1 service rifles from the USN SAMCU are the only service
rifles ever used by anybody making the US Palma Team; nobody's ever made the US
Palma Team using an M14 (for readers thinking the M14 or M1A is an excellent
long-range rifle...). In machine rest tests, the USN M1s shot about 30% more
accurate than those from the US Army or US Marine Corps marksmanship units.

An interesting thing about these match-grade 7.62 Garands. The most accurate
of all of them were built by a former USN Pistol Team member. He shot pistol
for many years and was pretty good at it. He was also on Ford Island in Pearl
Harbor on the morning of Dec. 7, 1941 as a young 3rd class petty officer. Two
years later, he was promoted to Chief Petty Officer. When he retired from the
USN in the late '50s, he went to work as a mechanic for the government and soon
ended up at the USN SAMCU. He worked very close with Charlie Frazier to learn
what really was needed to make the M1 Garand shoot virtually as good as the
best bolt action match rifles of the day. His name is Don "Mac" McCoy. Still
alive and well in San Diego.

Sometime in the 1970s, there had been enough problems with people trying to
insert a clip of 30 caliber ammo into a 308 M1 and having the rounds not
chamber. The USN designed a white, plastic like insert that went in the
receiver to prevent a clip of 30 caliber ammo being put in.

Of course, it was also not cool for someone going to a match at Camp Elliot in
this era with a 30 claiber M1 and not knowing this, then drawing 7.62mm ammo to
shoot. After a dozen or so empty cases laying nearby were observed to not have
any shoulder on them, the user oft times didn't get concerned at all. In fact,
a couple of folks shot all 50 or 60 record shots this way and didn't even know
it.

By about 1973, all the match-grade 7.62mm NATO Garand barrels had been used up.
There were a few service-grade barrels left but they were used in rebarreling
shot-out NATO Garands of USN Rifle Team members until they were gone by the
early 1980s.

Reloading for the 308

From: bartb@hpfcbart.fc.hp.com (Bart Bobbit)
Subject: Re: .308 loads
Organization: Hewlett-Packard Fort Collins Site

Although many different components are used in the .308 Win. for competition,
those that win most of the matches and set virtually all of the records are
seldom seen in print. For example, the use of ball powder seems to be a
popular thing, but ball powder has never produced off-the-shoulder accuracy
up to the level of extruded (stick) powder. Although ball powder meters
more uniformly and can produce equal-size groups at long range as extruded
powder from machine rests, it doesn't seem to perform as accurately as extruded
powder when fired from the shoulder. Most folks feel ball powder takes longer
to get the bullet out of the barrel than extruded powder and that's why scores
are higher when extruded powder is used.

Here's the loads that the top USA highpower competitors use to get sub
half-MOA groups in their bolt guns and sub MOA groups in their service
rifles:

* 200- and 300-yard favorites for service rifles:

> Federal or Winchester case, full-length sized.
> Federal 210M or Remington 9-1/2 primer.
> 42 to 44 grains of IMR4895 or IMR4064.
> Sierra 168-gr. bullet.

* 200-yard favorite for bolt guns:

> Federal or Winchester case, full-length sized.
> Federal 210M or Remington 9-1/2 primer.
> 40 to 41 grains of IMR4064.
> Sierra 168-gr. bullet.

or....

> Remington BR case, full-length sized.
> Remington 7-1/2 benchrest primer.
> 42 grains of IMR 4064.
> Sierra 168-gr. bullet.

* 300-yard favorite for bolt guns:

> Remington BR case, full-length sized.
> Remington 7-1/2 benchrest primer.
> 42 to 43 grains of IMR 4064.
> Sierra 180-gr. bullet.

* 600 through 1000 yard load for service rifles:

> Federal or Winchester case, full-length sized.
> Federal 210M (a uniform lot, if you can find one) or RWS 5341 primer.
> 43 grains of IMR4064 with the Sierra 180-gr. bullet.
> 44 grains of IMR4064 with the Sierra 168-gr. bullet.
Note - Cartiruccio bullets in the same weights are also used with
great success.

* 600 through 1000 yard loads for bolt guns:

> Uniform case as light weight as possible, such as WCC58 or WCC60, the
> earlier Winchester cases, full-length sized.
> RWS 5341 primer.
> IMR4064 powder, charge weight as follows for different case weights;
+ 42.5 grains in case weighing about 150 grains (WCC58).
+ 42.0 grains in case weighing about 157 grains (WCC60 or early
Winchester cases).
+ 41.5 grains in case weighing about 165 grains (current Federal,
Winchester, or the '92 Winchester Palma cases).
> Sierra or Cartiruccio 190-gr. bullet.
Note - Sierra's 200-gr. or Berger's 210-gr. bullet can also be used
if the powder charge is reduced about 1 grain.

or...

> Remington BR case, full-length sized.
> Remington 7-1/2 primer.
> ~43 grains of IMR4064 with a Sierra or Cartiruccio 190-gr. bullet.
> ~47.5 grains of IMR4350 with the Sierra 200-gr. bullet.
> ~42.5 grains of IMR4064 with the Sierra 200-gr. bullet.
> ~42.0 grains of IMR4064 with the Berger 210-gr. bullet.

Although Federal's 210M primer is very popular, it does not have the
shot-to shot uniformity as the RWS-5341 primer for use at the longer ranges.
It's also a bit too hot for the most accurate loads at long range. RWS's
No. 5341 is a milder primer and is more uniform both within a lot and
between lots than the 210M. Remington's 9-1/2 primer has been very good
when a uniform lot is used. The issue seems to be that milder primers give
smaller groups than stronger ones. Which makes sense as the bullet's base
will be deformed less when the initial pressure curve rises slower due to
milder primers than faster with the stronger ones. In all my tests for
accuracy, milder primers have always produced smaller groups than stronger
ones at ranges of 300 yards or greater. At 200 yards or less, the primer
intensity doesn't seem to matter that much. When the Remington 7-1/2 BR
primer began showing up in highpower matches for use at 300 yards, one of
the first thing that happened was the 300-yd. rapid fire record immediately
jumped to 200-18X and other 300-yd. scores improved. It was also used in
1987 to up the Palma course record to 450-29X over the earlier 450-22X score.
Primers are about 60% of the accuracy a load produces. The best way to test
primers is with a chronograph. Those that produce the lowest and most uniform
velocities typically deliver the smallest groups.

A lot of hoopla has been in print about Berger's 185-gr. Very-Low Drag (VLD)
match bullet. But they actually have a lower ballistic coefficient than
Sierra's 190-gr. bullet as proved in remaining velocity tests at 1000 yards.
And the Berger 185-gr. bullet seems to be a tad less accurate than a good
lot of Sierra 190s; the equal of regular lots.

I'm beginning to think Sierra's 155-gr. Palma bullet is an excellent choice
for service rifles. In a 1:12 twist, they can be driven fast enough in a
22-inch M1A or M14 barrel (also the 24-in. M1 barrel) to spin them fast
enough to stablize them yet not so fast to cause those not quite as well
balanced to be less accurate. The only limitation is they can't be shot
fast enough in service rifles to remain supersonic at 1000 yards. An
excellent load for this bullet in either service rifles or bolt guns is:

* Federal or Winchester case weighing about 165 grains, full-length
sized.

* Federal 210M or RWS 5341 primer.

* 44.5 grains of IMR4895.

BB

So when are you going to come out to the range again with it?

Right after tax season I take out the old boy. I'll send you a text.

More about the 308

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: 308 vs. 30-06.
Organization: Hewlett-Packard Fort Collins Site

Brent Danielson (jessie@iastate.edu) wrote:

: Why is it that handloaded 30-60 can't be made as accurate as a .308
: given the same quality of rifle?

Because the '06 powder charge is longer and heavier. That tends to
be more difficult to uniformly ignite and delivers a harder blow to
the bullet before it gets into the rifling.

: In fact, I would think that a 30-06 could be more accurate since
: there is the option of loading it with more powder and getting the
: bullet to the mark quicker - thus reducing the opportunity for wind
: drift and other environmental anomalies.

A common belief, but it doesn't prove out in reality. Competitive
shooters would rather have a cartridge that is more accurate even if
the bullets leave the barrel 100 fps slower. The difference in wind
drift is overcome by the smaller cartridge shooting much smaller groups.
The '06 can shoot a 190 gr. about 100 fps faster than a .308. That gives
a one-half inch deflection advantage per MPH of crosswind at 1000 yards.
In real deflection, it's 9 inches for the .308 versus 8.5 inches for the
.30-06. With the best '06 match rifles shooting about 13-inch groups at
that range, their size opens up horizontally to about 30 inches with a
crosswind varying +/- one MPH. The best .308 rifles at 1000 yards
shoot about 7-inch groups. Those would increase horizontally to about
25 inches with the same crosswind variance. So, the increased velocity
of a .30-06 is in reality not an advantage compared to the .308 Win.
However, given equally accurate cartridges, less wind deflection of
one over the other would be an advantage.

In the '50s , when the .30-06 was the only cartridge allowed in highpower
competition for most matches, the best of 'em would shoot 5- to 6-inch
groups at 600 yards. The target used at 600 yards had a 12-inch V-ring
inside the 20-inch 5-ring. Shooting possible scores at 600 yards was
an every day thing. Then along came the .308 Win. and folks immediately
found out that in equal quality rifles, that new cartridge would shoot
groups half the size as the venerable '06. Scores instantly became much
higher and a few years later the target's scoring ring sizes were made
smaller. It was attributed to the .308's shorter and smaller powder
charge. Perhaps other things helped too, but it all boils down to the
fact that the .308 Win. has better accuracy at all ranges through 1000
yards.

Outside of competitive shooting, the difference between these two
cartridges is miniscule.

BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: Inherent accuracy of different calibres
Organization: Hewlett-Packard Fort Collins Site

C. Daniel Myers (myersc@ucs.orst.edu) wrote:

: I keep hearing how .308 Win is more accurate than .30-06 Springfield.
: Is this true?

Yes it is true. The .308's improved accuracy is why the NRA reduced the
scoring ring sizes on highpower competiton 200 and 300 yard targets in 1966.
And the 1000-yard target's scoring ring sizes were made smaller in 1971.

Reasons why the .308 Win. is more accurate than the .30-06 are primarily
due to its smaller (lighter weight) powder charge:

* Being the same diameter, but shorter in length, it ignites and burns
more uniformly. This results in smaller velocity spreads which means
vertical shot stringing is smaller. Tests in the early 1960s showed
the .308s cut vertical group size about in half over the .30-06.

* As the smaller charge causes the front slope of the pressure curve to
not rise as fast, the bullet is pushed more gently into the throat/leade.
This causes less bullet deformation which results in the bullet being
less unbalanced as it leaves the barrel. More balanced bullets shoot
more accurately than less balanced ones.

* Another reason is barrel twist. .30-06 barrels standardized on a 1:10
twist in the early 1900s. That is way too fast for best accuracy with
150 to 180 grain bullets they mostly used. A 1:12 twist would have been
much better but folks didn't understand that at the time. With the .308
having 1:12 or 1:11 twists, their slower-velocity bullets were perfectly
stabilized and they shot smaller groups. Only with 200-grain bullets
did the .30-06 hold its own, but they had to shot with maximum charges
and that meant recoil started getting difficult to consistantly manage.

The best 600-yard groups competition .30-06es got in the 1960s was about
5 to 6 inches for twenty shots. As the .308 Win. cut that in half, the
bigger matches would have the top five or so competitor's with the same
perfect scores; tie breaking became a nusiance. With a few people having
a score of 100-20V, the NRA's tie-breaking rules didn't work; match
sponsors had to share awards between two tieing scores.

On those old military targets, the B target used at 600 yards had a 20-inch
5-ring and its V-ring inside was 12-inches. Putting 20 record shots inside
the V-ring happend once in a while. But the 1966 decimal midrange (MR)
target has a 12-inch 10-ring with a 6-inch X-ring inside of it. Now, the
discrimination between scores and competitors is much easier to make. Yes,
perfect scores are still shot on the new target; the record is 200-19X.

But in the pursuit of game animals, the differences are rather small when
sporting rifles are used.

BB
Index Home About Blog

Awesome stuff!!!

I don't have a huge collection of .30 cal US rifles, have a couple Garands and one M1A in the safe, but really enjoy shooting them. So this was a treat to read. Very enlightening, thank you!

So I have 4 CNO trophy rifles, two 30 cal, and two M1 MKII mod1's. one is a B grade. Mine has the AMF DEC 65 stamp on the barrel. I have stood in Don McCoy's garage in San Diego. Without a doubt my choice for long range service rifle is the MKII mod 1. That's the non-sleeved barrel. I went distinguished with that rifle.

M1 Reloading Basics

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: Need Help RELOADING for an M1 GARAND!!
Organization: Hewlett-Packard Fort Collins Site

Reloading for the M1 Garand is much like doing so for any semiauto rifle.
There are three general rules you should follow:

* Do not use powder that's slower than IMR4320.

Doing so will create much higher than spec'd gas port pressures and
that will put too much force on the operating rod. This excessive
pressure will be enough to bend the operating rod. It can also
cause the receiver to crack at the back as the bolt slams against it
with too much force. I've seen about half a dozen M1s that have
been ruined by the use of too slow of powder; their owners thought that as
this powder (4831, 4350) worked fine in a bolt action rifle, it would
be fine for their M1.

IMR4064 was the favorite powder when the M1 was extensively reloaded
for to compete in highpower matches. About 47 or so grains with a
Sierra 168-gr. bullet was used to win a lot of matches. Although 4895
was used for both ball and match ammo as loaded by military arsenals,
4064 produced much better accuracy and longer barrel life. In addition,
4895 is a fairly dirty powder and often requires barrel cleaning more
often than when 4064 is used. 4895 was (and is) used in military
ammo because it meters more uniformly in automatic powder measures than
4064; for handloading and weighed powder charges, 4064 produces better
accuracy.

* Full-length size the cases, but do not set the shoulder back any more
than about .003-in. from what a fired case measures.

To do this, you'll need an RCBS Precision Mic, a great tool that lets
you get the most reloads from your brass. When the case shoulder is
set back more than .003-in. from the fired case dimension, excessive
case stretching will occur each time the case is fired. This really
shortens case life, and, in many situations, you get only 2 reloadings
from a case. By keeping the shoulder setback on fired cases from an
M1 to about .003-in., you should get about 4 or 5 reloads from each
case, then the case should be destroyed and trashed.

* Seat the bullets out as far as possible to function through the
magazine area, but ensure they are at least .020-in. back from the
lands.

This will enable the most accuracy the barrel will deliver. It also
prevents a bullet from jamming in the lands and staying there should
you need to remove a loaded round from the chamber.

If your barrel's groove diameter is a bit on the large size, like about
3083 to .3087, Sierra and other US made match bullets may not shoot too
accurate. With this large of groove diameter, the Lapua .3092-in. diameter
match bullets will probably be the most accurate.

I suggest you use commercial cases for best accuracy. Although many folks
are enamored with the military cases with the word `MATCH' in their head
stamp, those cases are not very uniform in weight and thickness.

BB
From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: M1 reloading
Organization: Hewlett-Packard Fort Collins Site

Kirk Hays (hays@SSD.intel.com) wrote:

: Depends on the factory load. Federal makes a "Lake City Match"
: duplicate that is ideal for the M1. Anything with a bullet weight
: over 160-165 grains is probably a no-no.

For years, the Navy's standard long-range load for 7.61 M1 match rifles
was:

* LC case and primer; new.
* 44 grains of IMR4320.
* Sierra 190 seated about .050 short of land contact.

And boy howdy, did the rifle really kick! But from prone, it was bearable
for 25 or so shots. The most accurate long range load it was.

BB
From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: M1 Rifles
Organization: Hewlett-Packard Fort Collins Site

Ron Phillips (crphilli@hound.dazixca.ingr.com) wrote:

: Bart, why? I shoot 150 grains at DCM matches and 180 grains other times.
: Wasn' the "match" ammo used by U.S. Army snipers something like 179 grains?

Two things are going on here, I think.......

First, the standard USA military sniper rifle has been a bolt action rifle,
not a semiauto. So bullet weight isn't an issue. A few M14s were used as
sniper rifles and they used the M118 7.62mm NATO Match cartridge.

Second, the M2 30 caliber bullet (originated around 1920 for long-range
machine gun fire) weighs about 173 grains. It was used in the older M72
30 Caliber Match ammo produced by Frankfort and Lake City Arsenals.
The same bullet was used in the XM118 and M118 7.62mm NATO Match ammo.
The M118 Special Ball sniper ammo uses the same 173-grain bullet.

BB

Bedding Reasons

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Newsgroups: rec.guns
Subject: Re: Bedding and Bart
Date: 22 Apr 1994 13:45:57 -0400

Accuracy is the reduction of all variables to zero. Or at least as
close as us mortals can get them. One of these variables is where the
muzzle points as the bullet exits relative to the line of sight. That
pesky barreled action is like rubber; hard rubber laying on a chunk of
wood. Smack that hard rubbery thing with something and it's gonna be
bounced off of that piece of wood; but it ain't gonna come back down
to exactly the same place.

Examining the difference between a stock without epoxy bedding and one
with epoxy bedding for the same barreled action, we note that when the
epoxy bedded stock is used groups (scores?) are excellent. But when
the plain stock is used, scores (groups?) are horrible. Even when the
same ammo is used. So, there must be a reason. There is. Bedding.

When a rifle fires, its barreled action whips and vibrates all over
the place in every direction and various magnitudes. Such physical
trauma results in the receiver finally settling down in a microscopically
different place after each shot. After which it now gets to start
the vibrating and whipping all over again when the next shot is fired.

But that microscopically different starting point causes the barreled
action to take off in a different direction and magnitude than before
when the next shot is fired. This just repeats for each and every shot.

As the muzzle points in random places for each shot due to these whips
and vibrations, it will point at a different place relative to the line
of sight for each shot. That is what causes groups (accuracy) to be
less than what makes smiley faces. Barrel weight doesn't reduce this
situation. Neither does handloads with extremely low velocity standard
deviations. It is further aggravated by out-of-square bolt faces and
locking lugs not making full contact. If the barrel touches part of
the forend, that adds another accuracy-degrading element to an already
bad situation. And the best cases, primers, powder and bullets so
darned perfectly assembled won't help either. If the barreled action
doesn't start from the same place for each shot, the bullets won't end
up in the same place later.

So, if the barreled action can be somehow returned to exactly the same
place in the stock for each and every shot, the magnitude of those
barrel whips and vibrations will be greatly reduced, if not practically
eliminated. Then the only thing left is normal barreled action vibrations
at their resonant frequency, but this can't be eliminated although it
has virtually no effect on accuracy. Epoxy bedding was and is the
solution.

With the proper epoxy material being a near zero-tolerance fit to the
receiver, there's no room for the receiver to move around in from shot
to shot. Clearance between the receiver and the epoxy is .0001-in. or
less. That tolerance is at all places around the receiver. With
the correct torque on the stock screws, that receiver will go back to
the same position with the same tension so darned repeatable from shot
to shot that the accuracy is the equal of a barrel clamped in a machine
rest with just the action hanging on the back end.

Benchresters moved one step further some years ago. After expoxy bedding
their receivers, they removed the barreled action, roughed up the bedding
surface and the receiver, then glued the stock to the receiver. That
made sure the barreled action started its high-on-the-Richter-Scale moves
from exactly the same place, plus it eliminated the need to check the
stock screw torque a few times during the shooting day.

If one does not reduce the physical variables their own body has as part
of the complete shooting system, they may be large enough to mask any
improvements that have been made to the rifle and/or ammo to make the
mechanical parts of the system a flawless performer. Sometimes, that
does happen.

BB

------

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Newsgroups: rec.guns
Subject: Re: Bedding and Bart
Date: 22 Apr 1994 13:46:09 -0400

Gary Coffman (gary@ke4zv.atl.ga.us) wrote:

: .....it would seem that
: the inaccuracy caused by the necessarily loose fit of gun to shooter
: would overwhelm any looseness of fit in the rifle itself. Comments?
: Explanations?

I went through the receiver bedding stuff earlier. Now here's the
rest of the story.

`Bedding' a rifle to the shooter is equally as important. The rifle
must be held with the same pressure at all its person-contact points
just like the receiver in its stock-contact points. Here's why.....

After the bullet starts down the bore, Newton's Law becomes a very big
issue. The heavier the bullet, the more force needed to push it out
the bore. Seems the pressure behind the bullet also pushes back on the
inside of the cartridge case with about the same amount of force. As
a .308 Win. bullet goes down the bore and arrives at the muzzle going
about 2600 fps, the rifle has moved backwards about a tenth of an inch
as well as tilting upwards due to the center of the buttplate being
below the bore (hence pressure) axis. And it twists opposite the
direction of the rifling twist. How much it moves depends on how
firmly the rifle is being held; if tight, it won't move much at
all.

If the amount of shooter-holding/resistance varies from shot to shot, there
is no way the rifle will move the same amount in the same direction as
the bullet goes from case mouth to muzzle. Therefore, although the
sights were dead center on the target when you heard the shot being
fired, by the time the bullet gets out of the muzzle, its path ain't
where you'ld like it to be.

It takes about 3 milliseconds for a .308 bullet to go from case mouth
to muzzle. During that time is when the rifle recoils and whips about.
Some examples of what causes the bullet to end up striking the target
at an undesirable place are:

* Butt held too low in shoulder lets less mass be behind it; no shoulder
bone behind it, just flesh. The rifle's butt slips down a bit during
recoil which moves the muzzle end up. Bullet strikes high above call.

Almost the same thing happens with different shoulder pressure; it
causes vertical shot stringing.

* Cheek pressed hard/soft on buttstock changes resistance laterally or
vertically depending on pressure axis. Bullet will strike in any
direction away from call.

* Forehand held at different places with different pressure on forend;
all kinds of pressure point/axis differences. Amount of rifle movement
during bullet barrel time varies. Bullet strikes typically high and
low relative to call.

A good example is shooting prone with a sling. Once in position,
do not move your front elbow; the one on the arm with the sling on.
Use your other hand to adjust sights, pet dogs, throw rocks at your score
keeper, but do not move that elbow. If it moves out of place only
half an inch, your next shot will be one-half MOA off call; move that
elbow one inch and the next shot will be one full MOA off call.

* Pistol grip held differently for each shot. As the pressure applied
to the trigger gets transferred to the stock through the hand when
the sear releases, how that energy transfers to the stock while the
bullet is going down the barrel adds another dimension to where the
muzzle is when the bullet goes out. This is the main reason why light-
pull triggers enable the best accuracy; very little energy gets moved
into the stock and won't change muzzle position significantly. But
those four and a half ton triggers (sorry, 4.5 pound) on service rifles
used in competition.........no wonder it takes years and years for
most folks to master them. Three cheers for those 2 to 8 ounce wonders.

A good rule of thumb is to hold the pistol grip with hand pressure
equal to the trigger pull weight; at least. With heavy triggers, you
need to firmly grab the grip, otherwise, when a few pounds of force
slams back against the trigger stop, that firmer grip reduces the
amount of rifle movement the force causes.

All of which explains why free rifles have all those adjustable `gadgets'
all over them. Each part of the stock is adjusted to be a perfect fit
to the shooter's body. That way, the shooter's pressure on the stock will
be exactly the same from shot to shot.

And for those who marvel at those tiny groups benchresters shoot, even if
they are far back from winning anything.....well a great number of them
shoot free recoil; the rifle just rests on sandbags, then the thumb and
forefinger squeezes that 2-ounce trigger, the rifle goes bang and recoils
exactly the same amount in each direction. Every single shot. There is
no shooter contact with it except for the trigger. But that shooting
style isn't done in other disciplines. You gotta hold onto that magnum
you're gonna bust an elk with this fall; and that magnum moves about twice
as much before the bullet exits.

Rifle stocks are nothing more than an interface between the barreled action
and the shooter. Both things on either side of the interface vibrate and
move all over the place. If that interface is well fit to the metal at
one end and the flesh-and-bone thing at the other end, all the variables
of their fit will be reduced to zero; or pretty darn close that is.

BB

Bedding a Garand worth it?

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Newsgroups: rec.guns
Subject: Re: Bedding a Garand worth it?
Date: 24 Jan 1994 08:53:03 -0500

Considering the fact that all the service rifle teams epoxy bedded their
Garands to make them shoot more accurate with iron sights, yes, it's
worth it. Two areas need epoxy bedding:

* Receiver to stock.

* Handguards to barrel; permanent glue job, you gotta sometimes
break the wood off the barrel prior to rebarreling.

Epoxy bedding just the receiver and handguards will reduce groups
by about 25%. Refitting the gas cylinder and operating rod will reduce
groups about 25%. Eliminating play in the rear sight parts will also
reduce group size.

Epoxy bedding rifles improves their accuracy, if done right for the
particular design. It has nothing to do with the type of sights used.
All the sights do is let you use the accuracy; some sights do a better
job than others.

If the ammo one chooses to use isn't good enough to demonstrate the
improved accuracy, then perhaps the bedding job may not be worth it.

And finally, if the shooter can't tell the difference, again, the job
may not be considered worthwhile.

BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbit)
Newsgroups: rec.guns
Subject: Re: M1 Garand - NM conversion update.
Date: 13 Nov 1994 18:07:48 -0500

dave demartini (dd6582@nado.hp.com) wrote:

: The gas cylinder was hogged out to .645" to float it from the barrel. The
: small lug at the rear of the cylinder (aft of the hole for the bayonett
: rear seat) was also removed to prevent contact with it and the fore
: hand guard.

The rear of the barrel ring must not touch the front hand guard either.
Before the gas cylinder is put on the barrel, the three splines in the
barrel's front end should be peened just a little bit so the inner splines
of the gas cylinder will fit tight on the barrel; it needs to be very tight.
Then the gas cylinder lock should hand tighten to about the 4-o'clock
position and need to be tightened all the way to align with the gas
cylinder with a wrench. If the cylinder lock has to be backed off from
tight to align, it should be replaced with another one, otherwise, the
gas cylinder won't be tight and accuracy will suffer.

: The 'ring' in the center of the barrel (if you remove the three guards) taht
: the stock fits into was removed by drifing out the roll-pin. This was then
: perminently attatched to the fore-guard.

Both the front and rear handguards should be epoxied to the barrel.

: The aft-guard was relevied by .030" at the rear to give clearance for heat
: expansion of the receiver, and thus makes the aft-guard part of the
: barrel, and sort of 'floats' it with the barrel.

What? How much increse in length do you think the receiver will go when
it gets hot? If it's more than a thousandth of an inch or so, it will
compress the stock wood and become loose in the epoxy bedding. Besides,
if the receiver did lengthen, it would push the barrel forward and that
would take both handguards with it; the same clearance would still be
there. But the operating rod must not touch the rear handguard, so some
wood removal may be needed on the rear, right corner of it.

BB
From: bartb@hpfcla.fc.hp.com (Bart Bobbit)
Subject: Re: M1 Garand - NM conversion update.
Organization: Hewlett-Packard Fort Collins Site

dave demartini (dd6582@nado.hp.com) wrote:

: I have another question, however. Since the fore and aft guards are being
: attached to become part of the barrel, what about that lug that extends off
: the front of the stock, that slides into the bottom of the ring at mid
: barrel, that has the fore guard epoxied to it?

That `ring' is called the lower band. The stock ferrule has a lip that
fits into the bottom of the lower band and after the receiver is bedded,
there should be about 30 pounds of downward pressure on the lower band
as the stock's forend ferrule needs to do this. This downward pressure
is set up by the stripped barrel being held off the upper part of the
stock ferrule about 3/16ths of an inch or so when the receiver is bedded;
I don't know the exact spacing. But this is critical to accuracy; without
this downward pressure, the M1 won't shoot very accurate.

: Would it not make sense to saw off this lug, thus totaly 'free-floating' the
: barrel and guards? Neither article mentions doing this, but one of them does
: say to grind out .005" to .010" of the lug to allow for gas rod clearance,
: which I have done.

This is not how its done. The operating rod has plenty of clearance
without removing metal from the inside of the stock ferrule. Removing
metal from the inside of the ferrule's lip weakens it. And the ferrule
should be epoxied onto the stock's front end.

: I was just thinking about this as I'm done checkering the
: stock, and ready to do the glass bedding.

By the way, checkered M1 stocks are not legal for highpower competition;
that's an external modification.

BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: Bedding questions
Organization: Hewlett-Packard Fort Collins Site

Peter Prun (pprun@august.mtt.it.uswc.uswest.com) wrote:

: On the subject of bedding an M1 Garand:

: - How long would a bedding job last on a non-lugged receiver,
: assuming a proper job? (in rounds of ammo)

: - How long would a bedding job last on a lugged receiver,
: assuming a proper job? (in rounds of ammo)

Probably through 5 or 6 barrels; that's 30,000 rounds. But the non-lugged
recievers are better. Those lugs tend to crack loose. The best M1 match
conditioner on this planet gave up the lugged recievers a couple of years
ago; they just didn't work.

The lug will probably crack loose from the reciever before the bedding
goes. With either reciever type, you should loosen the trigger guard when
not at a match. This relieves the bedding tension and the bedding will last
for a long time.

: - How does one know when the bedding is failing? Does the
: accuracy get radically worse one day or is it a gradual
: decline? Is the accuracy of a rifle with cracked bedding
: still better than the average service grade M1?

Accuracy starts to get worse before the barrel is worn out. Like the groups
open up a quarter to half MOA. But the bedding typically doesn't crack, it
just pushes the wood away from where the bedding touches the reciever. This
is very common with original military stocks that were heavily impregnated
with stock sealer and oil-based finish. That stuff softens the wood that
no really accurate M1 should have the original stock. Get brand new wood for
the stock, then rout it out for the bedding. Finish the stock after the
bedding is cured and trimmed. Otherwise, the rifle won't be accurate for
more than a few hundred shots before the softened wood gives way.

BB
From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: Service rifle improvements
Organization: Hewlett-Packard Fort Collins Site

Here's some typical improvement numbers. Assuming a standard service
grade M1 or M1A/14 shoots 4 MOA at 600 yards with regular ball ammo
and the best of the `match conditioned' ones shoot 3/4ths MOA at 600
yards with proper handloads, the percentages for each section mean the
amount of the difference between service and match grade group size
that section will make up. The total of all sections will then equal
100%.

: 1) glass bedding of the barrel

Actually, the reciever is glass bedded, not the barrel. On M1s, the
hand guards are epoxied to the barrel.

Improvement: 20%

: 2) adding a heavier weight barrel

No improvement. Just makes the rifle easier to hold steady. Accuracy
is the same as a standard weight barrel of equal quality.

You didn't mention adding a top quality custom barrel. This is where
the biggest chunk of the accuracy improvement comes from.

Improvement: 40% (adding a quality custom barrel)

: 3) updating the sights to National Match

No improvement. Just cuts the movement per click in windage in half.
Properly tightened/adjusted service rear sights are just as accurate as
National Match rear sights.

: 4) updating the trigger to National Match

There is no such thing as a `National Match' trigger. If you mean
removing as much creep and backlash as possible, then stoning the
hammer and sear engagement for a crisp let-off, that's just doing
a `trigger job.' Like a heavier barrel, a good trigger makes the
rifle easier to shoot accurately, but has nothing to do with how accurate
the rifle is.

: 5) updating the gas system to National Match

Improvement: 5%

: 6) adding a thicker, more rigid stock

Again, this won't improve accuracy. But it will make the rifle heavier
and that's a help in shooting the rifle better. More important with
service rifles is that the stock doesn't warp. One of the synthetic ones
is better than a wood one, but not very much better.

: 7) changing the receiver to a lugged model

The guy who's built the most accurate M1 rifles this world has ever seen
has stopped putting lugs on them. They sometimes crack loose as they're
hard to weld on so they'll stay in place. Plus, the accuracy improvement
was a slight one and only worked as long as the lugs didn't crack in their
weld. M1A/14s have the same problems, but to a lesser degree. The best
thing to do with one of these recievers is to glue it in like the
benchresters do; break it free when the barrel needs to be replaced or
the gas system repaired, then re-glue it.

Improvement: 5%

: 8) using match ammunition

Government arsenal match ammunition quality varies somewhat; some lots
shoot good, other lots don't. Commercial match ammunition is usually
more accurate than government stuff. But neither are the equal of good
handloaded ammo. So there's three levels of improvement ratings:

Improvement: 20% for military match ammo (LC M852 Match)
25% for commercial match ammo (Federal, RWS)
30% for good handloads.

BB

Thanks for all your research. It’s great.

If you want to see some shoot, the LANTFLT matches are coming up in May at Quantico. There are normally a few MKIIs get pulled out if we shoot the 1K match on Range 4.

FA18hooker had quite a collection of trophy rifles awarded by the time he retired.

Garand Sight Markings

From: bartb@hpfcla.fc.hp.com (Bart Bobbit)
Newsgroups: rec.guns
Subject: Re: Garand Sight Markings
Date: 5 Jan 1995 11:56:53 -0500

On M1 rear sights, the elevation knob is marked in hundreds of yards.
The `2' means 200 yards, the 6 is for 600 yards and so on. Each click
is worth one MOA.

The windage marks on the receiver are worth 4 MOA per mark. Each
click is worth one MOA.

Here's how you `zero' the rear sight:

1. Turn the windage knob until the vertical line on the sight
base centers on the middle line on the receiver. The sight is
now at mechanical windage zero.

2. Turn the elevation knob counter clockwise until it bottoms.
Then raise it about 8 clicks.

3. Shoot the rifle at 200 yards.

a. Adjust windage by loosening the front sight with a 3/16ths
inch hex wrench, then move it opposite the direction you
want the group to move; don't forget to tighten it down.
You may have to make several adjustments to get it right.

b. Adjust elevation by turning the knob.

c. Be sure you have a good sight setting to center your group
on the target.

4. Without moving the elevation slide that has the aperture in it,
loosen the screw in the elevation knob, then move the elevation
knob until the `2' aligns with the mark on the sight. Then
tighten the elevation knob screw.

This should `zero' the sight. You can now set the elevation knob to
what ever range you'll shoot at and be real close.

BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbit)
Newsgroups: rec.guns
Subject: Re: National Match sights for Garand
Date: 9 Oct 1994 16:09:25 -0400

Larry Schuette (schuette@ait.nrl.navy.mil) wrote:

: What does the Globe front site buy me?

That globe front sight lets you use apertures on the front end. Apertures
are easier to align on the target. But aperture front sights are not
allowed on service rifles in matches for service rifles, such as DCM
matches. But in NRA matches, they are legal and the rifle is then
considered a match rifle. The highpower rule book explains the differences.

: Beside the apeture size, and the MOA per click difference
: what does the NM sight buy you?

NM sights have their parts fit to closer tolerances. Which means the
aperture won't bounce around from shot to shot and be in a different
position. I've seen a lot of commercial NM rear sights for 30 caliber
service rifles and they are so sloppily fit, they've got 2 to 3 MOA
of looseness in them. Which means even if the rifle is a tackdriver,
it can't be shot accurately because the rear sight doesn't stay in
the same place for each shot. A 1/2-MOA change on an NM rear sight
changes its position about .0039-in. If the elevation slide is loose
enough, the aperture in it will have several thousandths of an inch
slop and the 1-click change won't be noticed.

Good NM rear sights have their base and elevation slide lapped to a
virtual zero-tolerance fit. And the lock in the windage knob is set
to the correct tension, too. These sights should be checked with a
dial indicator on the rifle for repeatability. If they have more
slop than 25% of each click, they need fixed.

It's much like shooting a rifle with a scope. If the scope is loose
in its mount, or the mount is loose, the rifle won't shoot accurately
because the line of sight relative to the barrel is not the same for
each shot. Hold the aperture of a standard service sight and move it
around. You can see it move and stay in position several thousandths
of an inch from where it was.

: Can I just buy the smaller appeture and
: stick it in my normal rear sight

Not if you want good, repeatable sights. Although the smaller
NM aperture will give a better sight picture, the normal slop in
the service sight will still be there.

NM rear sight apertures rotate in the elevation slide. The hole
in them is offset from their axis by about .002-in. They have two
ball detents in them that fit in a groove in the elevation slide's
ring. A notch at the back of the hood indicates the position of the
aperture. If the notch is up, that means the aperture is at the top.
Rotating the hood 180 degrees to put the notch down relocates the
off-center aperture about .004-in. lower causing the effective sight
axis to go down 1/2 MOA. The elevation knob still moves the hood
1 MOA per click. So, you have 1/2 MOA adjustments in elevation by
rotating the hood to notch-up or notch-down.

Some folks have drilled out their service sight's elevation slide,
then grooved it to hold the NM aperture which is held in place by a
C-ring and washer on the slide hole's front end. But that's hard
to do a good job of because the slide metal is do darned hard.

BB

Accurate Primers

From: Lloyd D Reid <reidld@ecf.toronto.edu>
Subject: Velocity testing .308 Palma loads

I did some more testing at Jim Bullock's yesterday. I thought that
some actual test data may be of interest to the techno-masochists
here. I'd like to hear any comment/criticisms/questions on my
methods or results.

On the handful of occasions that I have chronographed loads, I have
always been disappointed at the uniformity of my loads. Even when
I employed the most careful loading techniques, I always seemed to
get velocity spreads of 100-200 fps, in a typical 5-shot string.
Hearing about sub-10 fps standard deviations here, made me cry.
I finally decided to get serious about it, and wrestle my velocity
deviations down to "rec.guns boasting territory" ;-)

My primary interest is long range target rifle shooting. We are told
that it is desirable to have as small a deviation in muzzle velocity as
possible. The reasoning behind this goal, is to reduce vertical stringing
at long range (800 yards - 1000 yards) due to shot-to-shot time-of-flight
differences. Even though a rifle may shoot a tight, round group at 100
yards, if different shots take more or less time to reach the target,
they will drop more (or less), leading to a vertically strung group.
(This is ignoring the complications of "compensation," and barrel
vibrations.) At these ranges, it takes over one second for a .308 bullet
to reach the target.

These time-of-flight differences make much, much less of a difference
at shorter ranges. At 300 yards and less, only a benchrest shooter
(if anybody) would notice the difference.

Bart Bobbitt has said that, in his experience, RWS primers have
given the best results. Federal match primers (as used in Jensen's
92 Palma load) are 2nd best, followed by Winchester, with CCI
"a distant last". Bart, please correct me if I've misquoted you.

His argument is that RWS provides the mildest, and most consistent
flame, which is (he argues) better. Since Bart is (much!) more
experienced than I, can shoot a helluva lot better, and seems
to make pretty rational arguments, I thought I'd give it a try.

In a previous article I mentioned that my results with RWS primers were
less than stellar. I was not at all impressed, and was getting ready
to declare to all the net that Bart was wrong, and I had proof! (Thought
I'd relish the rare opportunity ;-).

Bart replied that this was due to my loads being below max (I used 43.0,
44.0, and 44.5 grains of IMR 4895). He pointed out that my figures showed
a drop in SD as my charge was raised from 43.0 to 44.5. Well, I wasn't
convinced, but I thought I'd at least give it a whirl...

So, I loaded up 15 each of 44.5, 45.0, 45.4, 45.8, and 46.2 grains of
IMR 4895, using my standard "best" .308 loading techniques. Powder
charges were trickled to the nearest tenth of a grain (kinda time
consuming ;-). Note that these charges are quite hot, and are probably
not at all safe to try in any .308, without careful testing.

When the dust settled, there was good news, and bad news. The good
news is that I got far better uniformity in velocity than I ever
have before. The bad news is that Bart was right, and I'll have to
wait 'til another day before I can call him a liar in public ;-).

Remember that the object here is _not_ to gain the highest possible
muzzle velocity; rather, it is to get the most consistent load that
is safe, in _my_ rifle, under _controlled conditions_. I don't want
"excessive" pressures, because it's pretty discouraging to have the
primer pockets on your lovely hand-prepped match brass go loose,
and refuse to hold a primer for that wonder-load you just worked up.
I have yet to deprime these cases and see what happened to the tightness
of my primer pockets. The "success" of my experiment will of course
be contingent on how long my brass lasts; these are hotter loads than
I used last season.

OK, here's the data:

Rifle: My Winchester Model 70-based Palma rifle, caliber .308 Win.
Barrel is 30" long, .307" bore X .298" groove diameter, 1 in 14" twist
MacLennan barrel. Barrel had 2602 rounds fired through it since new.
Chamber is .308 Obermayer.

Chronograph: An older Chrony F-1, approx. 10' from muzzle. Sky
condition: overcast. Chrono seemed to pick up all shots fired.

All loads: '92 Palma brass, neck turned to 0.122", F/L sized with
Redding die to be 0.002" shorter than chamber headspace. The standard
0.3068" expander ball used, giving a measured 0.003" of neck tension.
(This is more neck tension than desired - I'm working on fixing this).
Bullet is Sierra 155 Palma, powder is IMR 4895, lot E93JA08 L7875.
Powder charges trickled to the nearest tenth of a grain on beam
balance, verified on electronic powder scale, before charging (i.e,
powder charges are +- 0.05 grains). RWS #5341 large rifle primers used.


First, some data from my earlier 18 Dec 93 tests.... these are what
Bart commented on.

Weather: mild, no wind, estimate temperature +5C/40F

43.0 IMR 4895, Winchester WLR primers (only test case to use
Winchester primers)
xbar= 2802.29 SD= 24.2501 Nsamples= 14
2822 2785 2830 2828 2822 2758 2783 2791 2809
2820 2830 2775 2774 2805

'xbar' is the average, "SD" is "sigma sub (N - 1)".

43.0 IMR 4895, RWS primers for this and all the rest:
xbar= 2812.42 SD= 51.1174 Nsamples= 12
2797 2818 2772 2772 2828 2809 2774 2755 2949
2805 2850 2820

Note that, within the SD, there is no difference in muzzle velocity
between RWS and WLR primers. And, the RWS-primed ones really suck.

44.0 IMR 4895: xbar= 2877.53 SD= 29.215 Nsamples= 17
2861 2869 2921 2936 2881 2863 2856 2865 2861
2877 2945 2881 2879 2854 2848 2848 2873

44.5 IMR 4895: xbar= 2908.12 SD= 19.1405 Nsamples= 17
2919 2912 2879 2906 2887 2925 2904 2896 2915
2894 2915 2896 2898 2883 2929 2927 2953


Yesterday's (12 Feb 94) testing:

Temp: (est'd) -10C/14F

Ammo temp: unknown. Since we were firing in a semi-heated enclosed space,
it was proabably "somewhat" warmer than outside temp. Have reason to
believe that ammo temp was fairly constant, for the duration of testing

Before testing, fired 3 'barrel warmers' - military surplus .308.
Chronograph survived this, so the day was off to a good start...

44.5 IMR 4895: xbar= 2864.13 SD= 15.2356 Nsamples= 15
2898 2859 2881 2887 2865 2867 2861 2850 2854
2859 2863 2844 2869 2842 2863

45.0 IMR 4895: xbar= 2872.4 SD= 10.1686 Nsamples= 15
2885 2887 2873 2879 2867 2869 2873 2859 2877
2850 2879 2885 2871 2865 2867

45.4 IMR 4895 xbar= 2912.33 SD= 7.0778 Nsamples= 15
2919 2915 2923 2908 2917 2915 2908 2915 2912
2925 2906 2904 2900 2906 2912

45.8 IMR 4895: xbar= 2950.8 SD= 17.1556 Nsamples= 15
2986 2945 2977 2940 2966 2951 2958 2962 2929
2951 2940 2929 2932 2938 2958

46.2 IMR 4895: xbar= 2960.21 SD= 14.0449 Nsamples= 14
2977 2968 2966 2950 2929 2968 2945 2973 2960
2960 2960 2947 2958 2982


Tabulated, we have:

Charge Velocity SD Speed per addtn'l grain of powder
44.5/RWS 2864 15
45.0/RWS 2872 10 16
45.4/RWS 2912 7 100
45.8/RWS 2950 17 95
46.2/RWS 2960 14 25

18 Dec 93 testing:
43.0/WLR 2802 24
43.0/RWS 2812 51
44.0/RWS 2877 29 65
44.5/RWS 2908 19 62


It doesn't look like the "speed increment per grain" is a particularly stable
number. Perhaps it is noisy because my sample size of 15 is too small?
Anyone out there play a statistician in Real Life? (That's your cue,
Henry....)

Well, it looks like what Bart said was true. Fancy that ;-) I will
run some more tests, centered around 45.4 grains. I'd like to get
SDs for a number of different runs, and see if I've really found
a 'valley' in velocity spread, or if the statistical noise is just
trying to enchant me..... Also, I will test ammo with slightly
reduced charges at elevated controlled temperatures, to get a better
idea of what will work at the range in summer, at 75F-100F. Hey,
I'm not _that_ wet behind the ears.. ;-)


That's it for the serious testing, here's two other tidbits:

Special test run on the side: 5 rounds of 44.5 IMR 4895 were cold-soaked,
to see what effect (if any) the cold primer/cold powder would have:
xbar= 2844.6 SD= 22.1991 Nsamples= 5
2846 2840 2822 2881 2834

compare this to the ambient (unknown ;-) temperature, probably about
5 or 10C warmer:
44.5 IMR 4895: xbar= 2864.13 SD= 15.2356 Nsamples= 15

It seems like the cold-soaked ammo was slower, and more erratic. I
dunno is it is statistically meaningful, though. Next time, I think
I will measure the ammo temperature, and see what I get from it.
I'll also run a larger batch of cold-soaked ammo.

Another thing tested was a quick'n'dirty groundhog load that I threw
together at the last moment: berdan primed military brass, a fairly
mild 44.5 grains IMR 4895 ('cause that's what my powder measure was
set up for ;-), and Nosler 125 grain Ballistic Tip bullets. This shot
~3/4" 5-shot groups, both from my Model 70 and from the ORA Mauser.
It looks like it has real potential, especially if the jerks behind
the trigger were a bit smoother ;-). This accuracy level is damn
near the best I can shoot from a bench (I'm no screaming hell of a
stool shooter, sigh).

I've only ever heard good things about Ballistic Tips. It seems like
they perform much better than one should expect from a sexied-up hunting
bullet. Boy, am I going to be hell on those groundhogs this summer....


- Daniel

Bullet Quality

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Newsgroups: rec.guns
Subject: Re: Bullet Construction and Performance
Date: 10 Apr 1994 14:44:42 -0400

Doug Lynch (drl00@lvld.hp.com) wrote:

: So I've been thinking about a few questions for you netters:

: 1) How much affect does the tip of the bullet have? Match bullets are
: typically hollow points. Wouldn't the Nosler BT "perfect point" have
: more accuracy potential than a hollow point or a lead tip that always
: seems to have some dents and imperfections in it?

The most accurate parts of a bullet are in two places:

* Bearing surfact to base junction uniformity. Hollow point bullets
are able to be made more uniform in this critical area. As that's
the last part of the bullet that leaves the muzzle, any irregularity
at this junctiol will cause the bullet to tip as it exits.

* Jacket wall thickness uniformity. As this determines how the bullet
is balanced, any non-uniformity in wall thickness will put its lead
core offset from its center of form. When spun at hundreds of
thousands of RPMs, any offset the center of gravity has from its
center of form will cause the bullet to wobble just like a wheel that
is out of balance.

: 2) Hornady builds their bullets with what they call a secant ogive shape.
: What really is this, and how does it compare to other bullet shapes?

A secant ogive is a raduis based on a trig function. Most bullets have
their ogive a true arc whose radius is typically measured in calibers, or
bullet diameters.

: 3) What about boattails versus flatbase bullets? What are the pros and
: cons of each?

Boattail bullets typically have flatter trajectories as their drag, or
ballistic coefficient is higher. But that advantage is not worth much for
ranges less than 500 yards because 99.999% of the groups folks and their
rifles shoot at longer ranges are larger than the higher BC advantage gets
them.

Commercial bullet companies have found that in factory barrels, flat-base
bullets may well shoot more accuratly than boattail bullets. In true
match-grade barrels, boattails do the best.

: 4) Some bullet makers manufacture their bullets with oversize tolerances.
: For instance, Hornady 30 cal bullets measure approx .308 while Lapua
: bullets can be had measuring .309.
: What real difference will oversized bullets provide?

Virtually every rifle barrel made shoots the most accurate when the bullet
diameter is at least five tenthousandths of an inch bigger than the bore's
groove diameter. In fact, bullet diameter can be as much as .0015-in. or
more bigger than groove diameter and peak accuracy still exists. One
advantage of shooting bullets bigger than groove diameter is the barrel
will last somewhat longer before accuracy starts to decline.

: 5) What about the internal structure of the bullet? How about the way
: the copper was drawn and does the type of lead used make a difference?

Jackets are first coined from a sheet of jacket material. Coining is just
stamping out round pieces. These `coins' are then put through several cup
and draw processes that makes the tube of jacket material with one end
closed. Next, the open end is trimmed to length. It's the wall thickness
of these jackets that is critical for accurate bullets. Match-grade
jackets vary only a few ten-thousandths in wall thickness; hunting bullets
about 2 to three times as much.

Lead cores may be pure or hardened lead. A large chunk of lead a few inches
in diameter is pressed in a swage that squirts out lead wire of the right
diameter. That wire core is next cut to the desired length. A machine
presses the core into the jacket. Finally, a pointing machine presses the
cored jacket into a die that shapes the bullet.

Pure lead cores are very homogeneous and therefore are used in match bullets.
Hardened lead cores are used for many hunting bullets so they won't expand
so fast. But hardened lead cores are not too homegenous; sometimes they
put the center of balance offset from the bullet's center of gravity. Which
is why hunting bullets aren't as accurate as match bullets.

: 6) How is ballistic coefficient calculated and how important is it in
: the performance characteristics?

Ballistic coefficients are calculated by time of flight between two points
that have chronographs. Sierra's Handloading Manual has about the best
explanation of this. Bullets that take less time to go from point A to
point B with the same velocity at point A have a higher BC than those that
take longer.

BC only tells us how fast a bullet's velocity will drop as it goes down
range. BC, by itself, has nothing to do with accuracy. But when coupled
with velocity, higher BC bullets typically have less vertical stringing at
longer ranges.

BB

Cartridge Comparison b/w 308 vs 30-06. A good article to read.

https://www.snipercountry.com/308-vs-30-06/