Anybody ever get good results with 155s in an M1A?

[Grump]

I've tried 3 powders, Noslers, Hornadys, SMKs and Lapuas and get anywhere from 1.5 MOA to 3.5 MOA, with most right at 2 MOA.

Velocities from the low 2700s to one little accident of 3 rounds at 2980. Powders have been Varget, 4064, and Ball-C(2).

 

[81STFACP]

Re: Anybody ever get good results with 155s in an M1A?

what is your 4064 load?

 

[Downzero]

Re: Anybody ever get good results with 155s in an M1A?

What's the twist rate of the barrel on an M1A?

 

[sandwarrior]

Re: Anybody ever get good results with 155s in an M1A?

If you've tried that many powders and bullets, and you shoot better with something else, you have a gun problem. I usually use 45 gr. of H4895X behind 155 Lapuas. But, all the powders you mentioned are within the 'down barrel pressure' limitation. Meaning all your powders are fast enough to use in the M1A.

What are you getting with other bullets? Where are they seated? How do the lands look? Everything I can think of says look at the gun not the bullets. And, of course, you are doing your part right? Have you had another shooter verify good/bad?

 

[Grump]

Re: Anybody ever get good results with 155s in an M1A?

I load mag length, usually 2.81 or 2.83.

175s are running .75 to 1 MOA with the best loads, 1.25-1.75 MOA with the ordinary ones.

Twist is 1:12.

Earlier testing with an old lot of 4064, older lot of
FC brass, 155 A-Max, WLR primers, 60F:

43.5 2720.3
43.9 2745.8 Was 1 MOA, very low SD, did not repeat on follow-up test.
44.3 2776.9

Varget, FA63M cases, WLRs

43.3 2748
43.7 2784
44.1 2793 All of these were about 1.5-2 MOA

Varget, FC cases (newer lot), 155 A-Max, CCI primers:

43 2677.1
44.2 2756.1
44.7 2786.1 Still not close to 1 MOA

Varget, WLR primers, 155s, can't remember if they were SMKs or Bergers, FA63M brass:

46.0 2857.2 2 MOA These sometimes don't extract fully

Ball-C(2)
45.3 2732 1.5 MOA (the earlier unsafe load was 3.5 MOA for 3 shots, so "push them faster" doesn't work at 2950 or a bit more from this barrel).

A-Maxes again, CCI 200s, 4064
45.1 2744.7
45.5 2800.8 Neither one any good.

A-Maxes again and Varget, CCI 200s
45.4 2827.6 Still no joy.

And so it goes.

I'm getting pretty much the same .75 to 1 MOA with FGMM 175s and Hornady Match 155 A-Max factory ammo. The Hornady load's performance is what inspired be to give the A-Maxes another try.

So, nice question, but what are YOUR results? In an M1A. I will occasionally have a group of three shots closely overlapping, then two other shots 1/2 to 3/4 inch away in different directions. Just not with the 2800 fps Hornady factory ammo with the A-Max.

 

[Grump]

Re: Anybody ever get good results with 155s in an M1A?

Anyone using them in an M1A?

Buehler??

Just double-checked and the last round of 175 SMKs was .90 inch at 100 yards for 7 rounds (checking CDB shot and verifying zero).

The 155 A-Maxes went into 1.7.

The 175 A-Maxes were 3 in .3, the other two out there for a total group of 1.57.

 

[sandwarrior]

Re: Anybody ever get good results with 155s in an M1A?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Grump</div><div class="ubbcode-body">Anyone using them in an M1A?

Buehler??

Just double-checked and the last round of 175 SMKs was .90 inch at 100 yards for 7 rounds (checking CDB shot and verifying zero).

The 155 A-Maxes went into 1.7.

The 175 A-Maxes were 3 in .3, the other two out there for a total group of 1.57.</div></div>

Grump,

First, you don' have second shooter verify. You've got to have a good shooter get the same.

Second by what I can crunch with all your numbers it seems pushing these pills is what's giving you the big groups. Remember the M1A was designed around the 7.62 using a 145-150 gr. bullets @ 2750. Or, approximately 50-100 fps slower than what the M1 ball ammo is loaded to for the M-1 Garand. I'm thinking the harder you push this the more your groups are going to stay big. Try loading your stuff to 2800 with H4895X. That is the perfect speed powder for these rifles. You may also try RE-15 to get a little more speed. Varget is a little on the slow side for a 155 bullet IMO for these gas rifles. Better for 165-175's maybe and up.

FWIW, the only loading of 150/155 bullets I did was with a friend and his M1A was with H4895X. That is THE POWDER that the M1's used and what the 7.62/.308 was brought into this world with.

 

[Grump]

Re: Anybody ever get good results with 155s in an M1A?

I'm confident on the shooter variable, as the 175s and 178s are still doing MOA or better every time, same rifle, same targets, same sessions, same shot calls. Sometimes 155s fired first, sometimes second, sometimes 1st and 3rd.

I was hoping for 2800, since the old military chrono of 78 feet translates into about 50 fps faster back at the muzzle (2750 with M80 was at 78 feet. Looking at more older results, it looks like they are all doing best at 2750. Gone as slow as 2670 or so and that was no good, 2725 was okay, and 2750-65 is as good as it gets...good enough to clean a HP target, but losing some Xs.

 

[sandwarrior]

Re: Anybody ever get good results with 155s in an M1A?

Losing some X's to accuracy or wind because you can't push them 100 fps faster? Or both, I guess. I can understand the frustration. Because in a normal situation you should be able to get 2850-2900 out of a long barreled rifle....accurately.

I also have to say, that FWIW, I've never attained the kind of accuracy I can get out of a bolt gun with a semi-auto. The AR-15's have come closest, but the M1A, best I've shot or seen shot on average for a specific lot of ammunition (handloaded) is just under MOA. Best single group just over .5. I think the M1A is a better 600-1000 gun than the AR. But, it's not as good as many bolt guns I've seen.