Took my M1A STD with JAE-100 G2 Stock to the range today...

[Retro]

I took my M1A STD (USGI H-R Chromed barrel) with JAE-100 G2 Stock to the range today.

With USGI walnut stock and cold barrel, I was able to get 4 – 4.5 MOA with mil-spec NATO surplus 7.62 x 51 at 100 yards.

Today, with the JAE100 G2 stock (with the JAE barrel tensioner set on the tightest setting), I improved to 3 MOA. And the felt recoil was reduced by at least 65% with the JAE stock.

But I noticed a few things, which was puzzling:

1. I will group 1.5 MOA groups if I fire a series of 3 shots without moving my cheek position. If I lift my head and then try to re-acquire my cheek position on the stock after each shot, my group will worsen to 3 MOA.

2. Resting on sandbags completely, I am getting an average of 3 MOA. Surprisingly, on Harris-pod while resting the rear of the stock on sandbag, I am achieving 2 MOA.

I couldn’t quite explain these findings. I tested over 50 rds today, with very similar results. My scope is a Simmons ATV. Do I really need a Leupold? Will Leupold eliminate the inconsistency of my cheek weld?

Please advise. Thanks.

Retro

 

[General Geoff]

Since you're getting tigher groups when you don't break your cheek weld, that means the rifle is fine. You must adjust your shooting stances, or possibly your optics.

Does your scope have adjustable parallax?

 

[Jason_G]

It's tough to give advice when you can't see the shooter, but to me the accuracy discrepancy when you are breaking your cheek weld says that you are not getting the exact same cheek weld every time, or you are not settling back into your NPOA. It might help if you pick an "anchor point" on your stock/cheek and make sure that you always rest your cheek against the same spot every time.

Best I can do from my computer.

Jason

 

[Retro]

No, no parallax on my scope, unfortunately...

 

[General Geoff]

That could be a big issue then. If your NPOA is off at all, then by breaking your cheek weld, every time you hunker back down to look through the rifle scope, your view of the crosshairs will be off slightly.

Adjustable parallax isn't just a gimmick. With a fixed parallax (let's say 50 yard), the crosshairs will remain stationary on a target at 50 yards. If you're looking at a target 100 yards away, and you move your head even just a little from side to side or up and down, the crosshairs will move in relation to the perceived location of the target, and thus you will instinctively make a minor adjustment to your aim, so that the crosshairs will once again be aligned with the target. Since your parallax is off, however, your aim will be off too.

The only reason you're getting great groups when you don't break the cheek weld is that your aim is off in a consistent manner. Precision vs accuracy. Gotta love it.

 

[Retro]

Oh wait, I went back and checked, I do have parallex, it is located at the front of the lens, and I have that set that to 100 yards...

I think it must be my shooting position then.

I don't seem have the same problem with AR-15... Very strange.

Also STD weight barrel is too sensitive to temperature difference... Maybe I should switch to a medium weight DMR barrel...

 

[Sunray]

"...Will Leupold eliminate the inconsistency of my cheek weld?..." Nope. The scope is just the sight. It just lets you see the target better and lets you place the shot better, but no scope will improve accuracy if the rifle doesn't shoot well with iron sights and the same ammo.
"...lift my head and then try to re-acquire..." I'd almost bet that the stock doesn't quite fit you properly.
"...surplus 7.62 x 51..." Milsurp ammo isn't made for great accuracy. Try some better ammo.

 

[Retro]

In the past, I have tried many types of ammo in the past... Hornady Match Ammo worked the best, but it only tightened the MOA by 0.5. Lake City ammo was the worst. I also tried some hand-loads, with varying results. I recently discovered the NATO Mil-spec ammo (made in Germany, I think), which on average worked as well as Hornady for my particular rifle. My friend's M1A, on the other hand, loved the Lake City stuff.

 

[Medusa]

Accuracy comes from consistency, may well be you don't get the same exact position that you feel comfortable in. You could put a small patch of tape or something non-abrasive on the cheekpiece, where you rest your cheek, to mark the spot. Also you may play with the rifle a bit, like relieving some tension and see how it works. it may depend what ammo the rifle likes, mine eats Lake City M80 pretty well.

 

[nbkky71]

Sounds like a nice rifle Retro. Do post some pics!

As far as accuracy is concerned, what you really need to do is shoot some Federagl gold medal match or USGI M852 ammo (both 168gr) through your rifle. That ammo is the gold-standard of accuracy in an M14/M1A. Granted, FGMM match is horribly expensive and M852 is hard to come by, but you need to set a standard somehow.

My M1A will fire M80 ball ammo, but accuracy greatly suffers. If you're only shooting at 100yds max, then you can probably get by with the ammo. If you ever plan on moving back to longer distances you'll want to tighten those groups up.

As fas as accuracy, there are 4 fundamentals to work on...
- consistent position
- consistent sight picture
- controlled breathing
- good trigger control

Master those and you'll see a vast improvement in performance.

 

[Wes Janson]

Go buy some Federal Gold Medal Match 168gr, Winchester Ballistic Silvertip 168gr, and maybe some 175gr if you'd like to experiment. Try those, and see how much smaller your groups are. From experience I know that I can expect both to group at least 1, maybe 2 MOA better than milsurp.