.458 SOCOM First shots

25 yards sitting freehand from the bench/table
(The first 5 shots can be seen in the target below all were to the right of the orange dot. They were Hornady 350 Gr Interlock FP, using IMR 4198 36.0gr and COAL 2.045.)
Now I need to decide on what optics I want to put on it for Pig Hunting.

Barnes TSX 250gr
IMR 4198 36.5gr
COAL: 2.100

Rifle Assembled from the following parts:
Aero Precision Lower w/MAGPUL STR stock and mil-spec carbine buffer and spring.
CMMG mil-spec trigger/LPK with MAGPUL + Grip and extended buttpad
Wilson Combat build kit with Wilson Combat 16" 1:22 Barrel w/10" TRIM Rail (waited over a year to get the parts...)
MAGPUL New PRO MBUS Front sight (Pros: Very easy to adjust. Down side, it doesn't have a locking mechanism to keep it from getting knocked into the closed position.)
YHM Rear sight

http://www.mdshooters.com/attachment.php?attachmentid=117423&stc=1&d=1398283458

Nice! How much does that thing kick?

My uncle has a Rock River .458 Socom for hog hunting. He has the Trijicon AccuPoint on his. He had some issues with FTE, FTF using Factory Wilson ammo but worked up some loads using Berger bullets that ended up working well after swapping out the buffer spring.

Where are you going Hogging? Take a few rounds and sight it in where you are planing to hunt. Even a moderate amount of elevation, temp, pressure has an impact on the ballistics of this round. He sighted his in Detroit, MI and we hunted in the hill country of Texas. Missed a hog (tried a headshot) high, turns out it was shooting 3" higher in Texas.

With those light bullets, you may be better off with pistol powder.

Save the rifle powders for the heavyweights.

The .458 is next on my list of uppers.

My 45-70's may get jealous though.

Klunatic said:

My uncle has a Rock River .458 Socom for hog hunting. He has the Trijicon AccuPoint on his. He had some issues with FTE, FTF using Factory Wilson ammo but worked up some loads using Berger bullets that ended up working well after swapping out the buffer spring.

Where are you going Hogging? Take a few rounds and sight it in where you are planing to hunt. Even a moderate amount of elevation, temp, pressure has an impact on the ballistics of this round. He sighted his in Detroit, MI and we hunted in the hill country of Texas. Missed a hog (tried a headshot) high, turns out it was shooting 3" higher in Texas.

Click to expand...

Thanks for the tip! We're planning on hunting in Georgia during our next trip to visit my daughter and son-in-law at Ft. Stewart. I've only loaded the Hornady FP 350gr and Barnes TSX 250gr. I have some Hornady 500gr I plan to load subsonic. The main issue now, as we're all aware, is trying to get powder. All I could find was the IMR which actually seems to be okay. I like the Trijicon's. Any issues with it and the recoil?

@Yoshi, I wouldn't say it kicks, but it has a good amount of push back/thump. It probably would rattle your teeth if you weren't holding it properly. I really like shooting it. I'm going to get some cinder blocks filled with sand and see how they hold up.

iH8DemLibz said:

With those light bullets, you may be better off with pistol powder.

Save the rifle powders for the heavyweights.

The .458 is next on my list of uppers.

My 45-70's may get jealous though.

Click to expand...

lol - Yep classic story of something old and something new

Dukes Defense said:

Thanks for the tip! We're planning on hunting in Georgia during our next trip to visit my daughter and son-in-law at Ft. Stewart. I've only loaded the Hornady FP 350gr and Barnes TSX 250gr. I have some Hornady 500gr I plan to load subsonic. The main issue now, as we're all aware, is trying to get powder. All I could find was the IMR which actually seems to be okay. I like the Trijicon's. Any issues with it and the recoil?

@Yoshi, I wouldn't say it kicks, but it has a good amount of push back/thump. It probably would rattle your teeth if you weren't holding it properly. I really like shooting it. I'm going to get some cinder blocks filled with sand and see how they hold up.

Click to expand...

No issues with recoil. Like you said it is more of a thump than a hard kick. Still not much of a chance at a follow up shot. I think my Uncle was using pistol powder as well, I will check with him on his hand loads and post up later for you. Did you try Maryland Reloaders in Waldorf for powder?

Klunatic said:

...Take a few rounds and sight it in where you are planing to hunt...

Click to expand...

Always good advice.

... Even a moderate amount of elevation, temp, pressure has an impact on the ballistics of this round.

Click to expand...

This is 2/3rds incorrect, yet often repeated.

Elevation (physical altitude) and barometric pressure will have almost ZERO effect on a 100 yard zero, and any effect (.14" per 5,000 feet (even possible between MI and TX?)) would be VERY buried on the noise even with an AR-15.

Do the math...find some facts...play with your ballistic software and demonstrate drop variations with environmental changes.

You will see microscopic changes at closer distances and differences at 300 yards hardly worth considering. Any issue like this 3" zero shift is clearly rooted in other causes and absolutely NOT due to physical altitude and/or barometric pressure changes.

Consider the following drop data, showing both a common rifle round (.308/175 grain/2,600 fps) and an example .458 SOCOM (300 grain/1,800 fps) at 0' above sea level and again at 5,000':

.308:
Distance / 0' ASL / 5,000' ASL / Difference
100 yards / 2.69" / 2.67" / 0.02"
300 yards / 26.77 / 26.09" / 0.68"
500 yards / 82.85" / 79.12" / 3.73"

.458:
Distance / 0' ASL / 5,000' / Difference
100 yards / 6.17" / 6.03" / 0.14"
300 yards / 75.21 / 70.55" / 4.66"
500 yards / 271.30"/ 253.65" / 17.65"

If we study "density altitude", it becomes apparent that barometric pressure changes are interchangeable with physical altitude with regard to air density.
We can easily see that altitude/barometric pressure changes amount to almost nothing.

We could also entertain the myth that air pressure changes, as manifested by barometric pressure changes due to regional air mass exchanges and/or altitude changes somehow affect internal combustion by "raising internal pressure" or "increasing the density of the air in the barrel".

Consider this:
A) Operating pressure of a regular rifle round is between 55,000 and 60,000 psi.
B) An atmospheric pressure change of hurricane proportions (1,013.25 millibars normal pressure down to 982 millibars for a huge system in 2002) only amounts to 1/2 of one PSI change in air pressure. 0.5 PSI...miniscule.
C) 0.5 PSI divided by 55,000 = 0.0000091 (0.00091 percent) - seems an insignificant change in chamber pressure.

So, to suggest that a change in atmospheric pressure will change interior OR exterior ballistics to the point of affecting a 100 yard zero is pretty much mistaken.


The correct part is that ambient temperature changes can sometimes have a measurable effect at 100 yards, but even this minor variation (assuming normal temp ranges and not leaving ammo in the sun, car, etc.) can be minimized with powder selection.

Just for the sake of entertainment, let us examine the effects of muzzle velocity due to temperature change, since that's the only thing left to affect it.

The published velocity for a .458 SOCOM with a 300 grain HP is 1,800 FPS from an 18" barrel, so this seems a fair place to start. If you disagree with what I ran across as a baseline, please provide viable ballistics and we'll look at those too.

So, if our 100 yard (sea level) zero is based on 1,800 fps and the raw drop is 6.17", what if we somehow cooked 10% more velocity out of our round? Of course, 10% on top of a normal load will likely rupture the case and wreck the gun, but heck, hold my beer and watch this (I'm getting used to VA...).

1,800 x 1.1 = 1,980. Raw drop at 100 yards at 1,980 fps 5.08".

6.17" @ 1,800 vs 5.08" @ 1,980 = 1.1".

Remind yourself that this is an extreme example, and 10% is indeed substantial.

A 1.1" difference in drop at 100 yards will be difficult to detect. There are other, more severely limiting factors, not only from a 1 moa rifle (the edges of the groups would be closer together than the individual bullets within either individual group, LOL), but even from the above average guy in a hunting situation.

He sighted his in Detroit, MI and we hunted in the hill country of Texas. Missed a hog (tried a headshot) high, turns out it was shooting 3" higher in Texas.

Click to expand...

Seriously, I'd have to wildly speculate that some other factor beyond simple environmental conditions caused any apparent zero shift.

I like numbers, but you just made my head hurt.

And that's why I refer to E.Shell as 'Yoda'.

Ed you just embarrassed my Uncle with math.