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M1A Load Development

Mongoose67

Sergeant of the Hide
Full Member
Minuteman
Feb 2, 2021
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Colorado
I have a M1A with USGI Parts kits and 1980's SA receiver. I have followed the accurizing instructions developed for Camp Perry. The only things I haven't done are ream the flash hider and I have not glass bedded the receiver. I was at the range yesterday working up a load with H4895 and 168gr Hornady ELD-M. I ran load developments from 41 to 42.9 in 3 gr increments. My best group was 2 MOA at 100 yds with 41.4 grs. My second best was 2.25 MOA with 42.3 grs. the rest were 3-4 MOA. I know this is a battle rifle, but should I expect better results than 2 MOA? I tried Varget and W748 and the results were not as good. My goal is for casual shooting and the infrequent boar or deer hunt.
 
Factory sights? I can help groups to use the NM sights. But the smaller peeper hole makes it harder to get on moving game.
 
With match grade ammo, typical results (3 shot groups)-
Custom built accurized - 0.50-1 MOA possible but 5 or 10 round groups typically 1-1.25 MOA
National Match or accurized: 1- 1.5 MOA expected but 5 or 10 round groups typically 1.5 to 2 MOA
USGI barrels, GI Contour: 3-4 MOA.

There are of course exceptions that perform better however, don't expect it.

Edit to add - even the 6.5CM M1As don't perform any better than the 308 versions.
 
With match grade ammo, typical results (3 shot groups)-
Custom built accurized - 0.50-1 MOA possible but 5 or 10 round groups typically 1-1.25 MOA
National Match or accurized: 1- 1.5 MOA expected but 5 or 10 round groups typically 1.5 to 2 MOA
USGI barrels, GI Contour: 3-4 MOA.

There are of course exceptions that perform better however, don't expect it.

Edit to add - even the 6.5CM M1As don't perform any better than the 308 versions.
I have a GI barrel. So I guess 2MOA isn't terrible.
 
I found this article years ago when I was smitten with the M14. You've probably read it, but just in case not:


He gets his Scout Squad down to, I think, 0.67 MOA.
 
I have had similar results with a M1A Loaded. They are certainly not bolt rifles. I think if you look at the M1A challenge postal the best guys were a little over 1.5 inch 5 shot groups at 100 (it may have been closer to 1) --typically with a Blackfeather stock.

NM guides call for a 10 shot 6 inch group at 300 yards (roughly 2MOA)
 
I have a M1A with USGI Parts kits and 1980's SA receiver. I have followed the accurizing instructions developed for Camp Perry. The only things I haven't done are ream the flash hider and I have not glass bedded the receiver. I was at the range yesterday working up a load with H4895 and 168gr Hornady ELD-M. I ran load developments from 41 to 42.9 in 3 gr increments. My best group was 2 MOA at 100 yds with 41.4 grs. My second best was 2.25 MOA with 42.3 grs. the rest were 3-4 MOA. I know this is a battle rifle, but should I expect better results than 2 MOA? I tried Varget and W748 and the results were not as good. My goal is for casual shooting and the infrequent boar or deer hunt.

3MOA will still kill a deer.

Been there done that.

Glass bedding and unitizing are the steps you need to do if you want an M1A that shoots worth a damn.
 
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Best I could ever get from mine was about 1.2 MOA.
All factory, NM barrel, with a scope. 168gr SMK with IMR-4064. Most loads I tried were 2-4+ MOA.
Swapping parts and screwing around with it never made it shoot better than it did stock.
Finally put all the factory parts back on it, sold it, and got an AR-10.
 
I've got a SA Super Match that's been worked over by Dave Sullivan a bit. M3A stock, Leupold MK4. It's pretty dam accurate as far as M1A's are concerned. It will hold around .75 MOA but ONLY when I do my part, if I'm lazy/undisciplined when shooting it, the groups will open up drastically. The M1A will show every tiny error or inconsistency you have as a shooter! I'd suggest spending a lot of time behind the rifle before spending too much time on load dev. I'd find a safe load that shoots well in other rifles and just run it for a while. FWIW I shoot 175 SMK's over 43.5gr Varget (don't start there), FGMM brass. The rifle doesn't seem too picky, it shoots 168 SMK's well and used to shoot factory 168 AMAX ammo extremely well.
 
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I'm running 42.4gr RE-15 behind a 175SMK in my "custom" built M1A. It shoots < 1MOA all day. It started as a SA receiver and was taken to a match at Camp Pendleton. An armorer from Crane NSWC was there that weekend working on people's guns. He happened to have a bunch of parts and ended up building mine up with some USGI internals, McMillan stock, and Krieger barrel. Shoots way better than my Supermatch.
 
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3MOA will still kill a deer.

Been there done that.

Glass bedding and unitizing are the steps you need to do if you want an M1A that shoots worth a damn.
Thanks. I have unitized the gas system. Just trying to decide if I want to try to bed it myself. I have done bolt action rifles. This seems more complicated.
 
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I went through all of this with mine and in the end I gave up and hired a gunsmith to bed it, rebarrel it, put it in a mcmillan stock all that stuff. It's the only way to get one of them shooting acceptably well.

Or sell it and get a cheap AR10 like the tread which will shoot just as well and never need bedding.

As far as loads go I used a lot of Lake City brass 43 grains of RL15 and 175smk to 2.81" or 41.5 H4895. Literally wore out my barrel using those two loads.

Never thought about hunting with it, after mcmilland and new barrel it weighed 15lbs not lugging it around when I have a 30-06 bolt action that weighs much less.
 
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I would just keep the rifle as is and enjoy the thing and not try to make it something it’s not. Guys do this stuff with AKM’a as well. I never understood it. Some people just like to tinker I suppose.

2MOA will kill deer easily to 300 yards which is further than most hunting shots typically are by a wide margin.
 
Have it bedded. Stick with H4895
To expound, the system is easily tuned with a powder developing 12,000 psi at the gas port using a simple one shot per increment of .3 grains Ladder at 100 yd and a 155-168 gr bullet in the 1:12 chrome lined usgi bbl. despite all the monkey motion, a clear node should appear. Rl-15 will shoot great until that day the temp rise bites you. Nothing slower than 4064 unless you drill the gas plug/groove the piston and intend to run heavies. The 155 Scenar has proved accurate and makes for a sweet shooting setup at 2620 out to 800. Proper bedding is Essential. Don’t bother until that is done. An adjustable gas plug (Schuster) can further improve the tune. Bamban on accurateshooter is a past master and a wealth of information.
 
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