Hornady 208gr. Amax in a .308 for long range?

[BenL]

I found this post on another forum:

308 Win
Win brass
208 AMax, moly'd
CCI 200
3.00 OAL
51 gr RL-17
2650 fps.

I intended to go long and check some drops so I bolted on the 16X Super Sniper. Shot two groups to get a 100 yard zero. First was four shots into .65", second was three shots into .65" again.

I then went out to a 1 moa wide white rock at 1320 yards. Dialed 46 moa per Quicktarget. Wind seemed very low and almost 6 oclock so I didn't dial any wind. First round was 1 mil left. I held one mil right, and the second and third shots were hits.

The general consensus in their discussion is that the 208gr AMax bullet has better terminal ballistics and bucks wind drift better than lighter bullets. Does anyone have any experience with these bullets in a .308? 2650 sounds awfully fast for a 208gr bullet from a .308.

[DZ]

RL-17 is reported to do very well in the heavier weight bullets. Check out the threads on practicalriflery. I think member oliveralan is messing around with that combination here.

Doesn't your Savage have a 1:10" twist? If so, you might be a good candidate for messing around with it.

[BenL]

Originally Posted by DZ

RL-17 is reported to do very well in the heavier weight bullets. Check out the threads on practicalriflery. I think member oliveralan is messing around with that combination here.

Doesn't your Savage have a 1:10" twist? If so, you might be a good candidate for messing around with it.

Will the 3" OAL be a problem?

[DZ]

Don't have an answer to that one. I use 175 SMKs loaded to mag length (2.800").

[BenL]

Originally Posted by DZ

Don't have an answer to that one. I use 175 SMKs loaded to mag length (2.800").

Yeah, that's what I'm starting with because it's tried and true, and i need something ready to go by the 25th. After that, I may experiment a little.

[cega]

I have a couple of boxes of the 208gr AMAXs sitting here to play with. This is initial load data from Hornady for this bullet:

208 AMX Initial Load Data:

308 Win- 208 Amax, WLR primer, Hornady brass, Win M70 22", 2.80", 1:12" twist

Varget-
Start load: 34.9 @ 2100 fps
Max load: 40.0 @ 2300 fps

IMR 4064
Start load: 36.2 @ 2100 fps
Max load: 41.0 @ 2350 fps

R15
Start load: 38.2 @ 2100 fps
Max load: 43.2 @ 2400 fps

Win 748
Start load: 37.9 @ 2100 fps
Max load: 44.6 @ 2450 fps


One thing to keep in mind is that there is a special seating insert for this round, at least for use in Hornday dies. I am planning on seeing about loading some up using the Varget load info but somehow I think it may be a bitch to get it down to 2.800" COL - almost certain to be a compressed load I'm thinking.

[Oliveralan]

I use this load exclusively in my .308, was one of the first along with some guys on snipershide to play with it. Heck I built my f-t/r rig around this. I am shooting 48gr RL17 touching the lands (around 3.1" oal for me) 5 shots 1/3 moa at 100 under .5moa at 400. From a 300yard zero I dialed 26.5moa to 1000. Also chronoed my velocity and it corresponds with my drop. Just around 2800fps. I have a 28" 1-11tw hart. Dot believe me? Well I plan on being at quantico April 25th. Kicks pretty hard though.

[BenL]

Originally Posted by Oliveralan

I use this load exclusively in my .308, was one of the first along with some guys on snipershide to play with it. Heck I built my f-t/r rig around this. I am shooting 48gr RL17 touching the lands (around 3.1" oal for me) 5 shots 1/3 moa at 100 under .5moa at 400. From a 300yard zero I dialed 26.5moa to 1000. Also chronoed my velocity and it corresponds with my drop. Just around 2800fps. I have a 28" 1-11tw hart. Dot believe me? Well I plan on being at quantico April 25th. Kicks pretty hard though.

2800 fps?? Holy monkey. Do you know what kind of chamber pressures you're getting? Have you tried these loads in a shorter barrel? Who's brass?

I might be taking a serious look at this bullet; I'm running a 1:10 24" barrel. I'm off to Bass Pro to see if they have any...

[cega]

Would love to figure out how to get this to cycle in my .308 DPMS, which limits me to magazine length rounds. Anyone built anything to get to 2.800" COL?

[cega]

Bass Pro was out the other day FIY

[BenL]

Originally Posted by cega

Would love to figure out how to get this to cycle in my .308 DPMS, which limits me to magazine length rounds. Anyone built anything to get to 2.800" COL?

The pressures might be too high to get any real velocity; especially in a DI gun. I saw some loads for 2.80" OAL, but the velocity was low (maybe 2400fps?)

[cega]

Post #6 above has info straight from Hornady as to 2.80" OAL loads, velocity ranged from 2100fps to 2450 fps.

I haven't had a chance to load any up yet, on my list of things to do.

[DZ]

According to JBM, that (2400 fps MV) should get you to 1000yd fine:

Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead 
(yd) (MOA) (mil) (MOA) (mil) (ft/s) (none) (ft•lbs) (s) (MOA) (mil) 
0 *** *** *** *** 2400.4 2.150 2660.8 0.000 *** *** 
100 -0.0 -0.0 0.2 0.1 2271.3 2.034 2382.1 0.128 0.0 0.0 
200 -2.3 -0.7 0.4 0.1 2146.3 1.922 2127.3 0.264 0.0 0.0 
300 -5.4 -1.6 0.6 0.2 2025.5 1.814 1894.5 0.408 0.0 0.0 
400 -9.0 -2.6 0.8 0.2 1908.4 1.709 1681.8 0.561 0.0 0.0 
500 -13.0 -3.8 1.0 0.3 1794.7 1.607 1487.3 0.723 0.0 0.0 
600 -17.4 -5.1 1.2 0.4 1684.1 1.508 1309.6 0.896 0.0 0.0 
700 -22.2 -6.5 1.5 0.4 1576.4 1.412 1147.6 1.080 0.0 0.0 
800 -27.5 -8.0 1.7 0.5 1471.9 1.318 1000.4 1.277 0.0 0.0 
900 -33.3 -9.7 2.0 0.6 1370.7 1.228 867.6 1.488 0.0 0.0 
1000 -39.7 -11.5 2.3 0.7 1273.3 1.140 748.6 1.715 0.0 0.0 
1100 -46.8 -13.6 2.7 0.8 1180.5 1.057 643.5 1.960 0.0 0.0

For reference: 175 SMKs @ 2680

Range Drop Drop Windage Windage Velocity Mach Energy Time Lead Lead 
(yd) (MOA) (mil) (MOA) (mil) (ft/s) (none) (ft•lbs) (s) (MOA) (mil) 
0 *** *** *** *** 2680.6 2.401 2791.7 0.000 *** *** 
100 -0.0 -0.0 0.2 0.1 2498.2 2.238 2424.7 0.116 0.0 0.0 
200 -1.7 -0.5 0.4 0.1 2322.8 2.081 2096.2 0.240 0.0 0.0 
300 -4.3 -1.3 0.7 0.2 2154.9 1.930 1804.1 0.375 0.0 0.0 
400 -7.4 -2.2 0.9 0.3 1994.3 1.786 1545.2 0.519 0.0 0.0 
500 -11.0 -3.2 1.2 0.3 1840.1 1.648 1315.5 0.676 0.0 0.0 
600 -15.0 -4.4 1.5 0.4 1691.7 1.515 1111.8 0.846 0.0 0.0 
700 -19.5 -5.7 1.8 0.5 1548.5 1.387 931.6 1.031 0.0 0.0 
800 -24.6 -7.2 2.1 0.6 1410.9 1.264 773.4 1.234 0.0 0.0 
900 -30.4 -8.9 2.5 0.7 1279.7 1.146 636.3 1.458 0.0 0.0 
1000 -37.2 -10.8 3.0 0.9 1156.8 1.036 519.9 1.704 0.0 0.0 
1100 -44.9 -13.1 3.4 1.0 1064.7 0.954 440.4 1.976 0.0 0.0

http://www.jbmballistics.com/cgi-bin/jbmtraj-5.0.cgi

ETA: windage was set at 3mph crosswind, for those wishing to compare...

[Oliveralan]

Yes I know 2800 seems pretty wild. Check out LRH, some guys there have tried it after I posted my preliminary results. They had similar results. I have zero pressure signs. I am using full BR preped Winchester brass and CCI BR2 Primers. I went up to 49gr but accuracy was best right at 48 for me. I will bring these as well as some 175 mk/RL15 loads for comparision to the next quantico match. Just found out I will be able to make it!!

I would seriously recommend not to try this in a gas gun! I remember a guy saying it was about 77k psi according to quickload. But don't quote me on it.

[BenL]

Originally Posted by cega

Bass Pro was out the other day FIY

Just got back. They had a few boxes of the 208gr., so I picked up 100 to try.

No Reloader 17, though. (they don't even carry it.) I hate paying for hazmat fees.

[BenL]

Originally Posted by Oliveralan

Yes I know 2800 seems pretty wild. Check out LRH, some guys there have tried it after I posted my preliminary results. They had similar results. I have zero pressure signs. I am using full BR preped Winchester brass and CCI BR2 Primers. I went up to 49gr but accuracy was best right at 48 for me. I will bring these as well as some 175 mk/RL15 loads for comparision to the next quantico match. Just found out I will be able to make it!!

I would seriously recommend not to try this in a gas gun! I remember a guy saying it was about 77k psi according to quickload. But don't quote me on it.

What do you mean by "BR prepped"? (I'm fairly new to reloading; less than a year). Do you mean like the level 4 bench prep on Ed's page?

Would CCI #200 change pressures compared to the BR2 primers?

Do you use a special "insert" when seating these bullets?

[E.Shell]

That the 1,000 yard velocity is above the speed of sound is nice, but not all bullets destabilize as they go through the trans-sonic velocities, so it may not be as critical as Sierra's 168 MK, for example.

A more important (IMHO) parameter is wind drift, since it is the condition we both have the least control over and the least ability to measure across the course of bullet flight.

For wind at 1k, using Dan's example above, we see .9 moa for the 175 and .7 moa for the 208 per 1 MPH of wind. This is great for a known distance match and .2 MOA at 1k is almost half of the X ring at F-Class. Almost anything one can do to the .308 to cheat the wind is VERY welcome.

For unknown distances, the edge fades and drop becomes excessive with the heavier bullets. In the chart above, there is more than 3 MOA (32") more drop at 1k with the heavier bullet. This means we can estimate range within 5% (50 yards) and still miss by almost three feet. In short, we trade horsesh!t for manure while sacrificing our ability to mag feed.

FYI, those guys getting the *very* high velocities are taking some extra steps:
1) using very long throated chambers, or at least longer than SAAMI
2) seating bullets very long to increase the combustion chamber
3) running longer barrels to capitalize on new powders
4) loading to pressures that exceed SAAMI ("safe") levels.

77 kPSI is WAY above where we want to be. I cannot imagine brass life when used at pressures beyond it's tensile strength.

For someone with a custom gun, the long heavy slugs **MAY** be driven fast enough to provide an advantage on a known distance course. The BIG question is whether we can achieve these velocities with safe pressures. We might also keep in mind that while published and estimated velocities are often cited, chronographed velocities may not meet our expectations.

For the "General Purpose" crowd, the 208s are too long to be practical, and when seated to clear the leade and/or magazine feed, they will intrude substantially into the powder space.

What about 155 Scenars (same BC as a 175 SMK) at 3,000+ FPS? Do the math....they rock and this was all the rage last year. Wonder what next year will bring?

BTW, CCI #200 and CCI-BR2 primers feature identical everything and come off the same production lines, but the BR primers are selected for consistency. I used to use a lot of BR2s and 210Ms, but I don't have any trouble getting good groups from precision field guns using standard CCI-200s and these are also what we use for F-Class.

[BenL]

Thanks, Ed. So essentially, the 175gr. SMK is a good balance of terminal velocity, safety, and (for the lack of a better phrase) ease of use.

If I understand correctly, loading the 208gr. may give some improved performance, but the pressures are excessive, require more attention when loading, and the improved performance is more than likely marginal with shorter barrels?

[E.Shell]

Without having a gun set up to shoot the 208s at velocities higher than those permitted by standard chamberings, there's no real advantage. Other than a few experimental minded shooters with specialty rifles, there's not a lot of popularity since the improvement is so marginal for the return. Only recently have powders been changed enough to consider this even feasible.

Oliver is getting very good results with his rifle, but it is purpose built by a good 'smith (using MY reamer, I found out...) and follows a different set of rules from factory guns and most customs.

Pressures are only excessive if you load them that way, which everyone seems to want to do so they can cash in on this tempest in a teapot. The problem is that 208s loaded to the SAME length and (SAAMI) pressures as the standard 175 (2,650 at 2.800") and the excitement is gone.

Load the 175s way out in the case and jump up to the pressures some of these guy are working to and also see a performance jump, but you'd be called "crazy" for doing that, because it's well known to be unsafe to hotrod handloads like that...

You could certainly try them in your rifle to see what they'll do. As long as some factory throats are, you may find that you can drive them fast enough to see any help.

If you're trying to get a working load together in time to load some for the 25th, you may want to stick with the very well proven combo of Varget & 175s just to make it easy on yourself.

[Oliveralan]

Ed,

thanks for the post. My load may be hot, and anyone trying this should start MUCH lower. I worked up to 50gr (just checked my data) and had no pressure signs. Like you said, this is a purpose built rifle for known distance F-class. It may be using your reamer but the throat was lengthened using s throating reamer to maximize case capacity.

BenL,
By BR prep I mean trimmed, neck turned, VLD chamfered and deburred, primer pockets uniformed, flash holes uniformed, and internal volume checked using really fine salt. I will also start indexing cases with the next batch.
Some people say they see no real improvement by doing these things, but I don't want to start compounding errors. So I try to control any variable I can. I want to know that if I miss or go off to one side or the other, it is my fault. And I don't have to question my equipment.