M1A being super picky?

[sniper20]

So I purchased a used M1A NM rifle a while back. I have tried and tried to get this thing to shoot, but haven't been able to find anything until today...

I broke down and purchased some Federal Gold Medal Match 168gn factory ammo, which shot about 1MOA. Each time I would shoot a group, 2 just about touch, and 1 flys off and opens it up to about 1MOA. Did it 3 times... don't ask me.

I FINALLY found that 41.0gn of A2520 shot pretty darn good today. 5 shots gave me about 3/4 MOA. Hornady 168gn HPBT, LC brass, annealed, FL sized, primer pockets reamed and uniformed. I didn't use the chronograph because I'm going for accuracy, not velocity. So I gotta tweak with that a little more to make sure I'm getting what I need, but it looks promising. I fired 3 times, shot some others, then the other two to confirm and they landed right where they should have.

I also found that 45.5gn of Staball Match shot well, but not as good. It also gave me 2 failure to extract cases... so I'm guessing it's either not good on the gas system, or its not good on chamber pressure...

Does anyone else have an M1A they shoot that is super picky? I just cannot believe that if I go 1 grain in either direction, this turns into a 5MOA group... I have never seen a rifle do that before...

 

[Choupique]

That's pretty bad.

It is a pretty complex rifle. Have you taken it all apart and put it back together again? Any sighns of oil soaking into the stock around the trigger group or the back of the action?

 

[sniper20]

That's pretty bad.

It is a pretty complex rifle. Have you taken it all apart and put it back together again? Any sighns of oil soaking into the stock around the trigger group or the back of the action?

This has the composite stock on it. Take it down to armorer level. When I got it, it appeared to have been unfired or very little. It shot today, MOA and going to confirm it tomorrow. But I have never seen such a big swing in group size.

 

[Choupique]

First thing I'd do is shoot a 9 or 10 shot group or at least overlay several 3 shot groups to see what the total spread looks like.

They're notorious for walking as they heat up but you'd notice that vs just plain shooting poorly. Look into what they had to do to get the M21 to shoot well. Its a lot. Its not the most accurate platform.

Iron sights? I know most of the scope mounting systems are weird and problematic, and the action is hard on scopes. I shoot a garand a lot, and I'd be tickled with a true 1 moa group.

 

[sniper20]

First thing I'd do is shoot a 9 or 10 shot group or at least overlay several 3 shot groups to see what the total spread looks like.

They're notorious for walking as they heat up but you'd notice that vs just plain shooting poorly. Look into what they had to do to get the M21 to shoot well. Its a lot. Its not the most accurate platform.

Iron sights? I know most of the scope mounting systems are weird and problematic, and the action is hard on scopes. I shoot a garand a lot, and I'd be tickled with a true 1 moa group.

I did that. FGMM factory ammo dropped about 2-3 MOA…

I usually shoot 5 round tear groups, but had my daughter with me today, so I shot 3 and then if it was good, I circled back and shot the remaining 2.

I literally had one group that would not have been able to stay in an 8.5x11 paper… it was horrible.

I understand they aren’t the most accurate, but damn… I figured a 3MOA rifle with about anything through it, and MOA with a good load. Mine is the National Match! It should shoot better than that. I gotta see if the one good group I shot will keep it together.

 

[Fireflyfishing]

Irons or scoped?

 

[Blowdowner]

Schuster adjustable gas plug might help.

 

[sniper20]

Irons or scoped?

Scoped. I know where you are going because it's the white rabbit I already caught... haha. It's the Springfield 4th gen mount, and despite what their directions say, it got some blue loktite on it... I had it come loose twice before. Before going out, I checked the torque of the screws and keep and eye on them during.

 

[sniper20]

Schuster adjustable gas plug might help.

I would love to have one... if I could find it. I know everyone says they are not needed, but I have one for my M1 Garand and absolutely love it. Makes the recoil better and saves the wear and tear the little it will get shot. I had no choice on that one. Factory plug went flying out during my first outing with that rifle...

 

[Choupique]

What scope? How's it do with irons?

 

[sniper20]

What scope? How's it do with irons?

Vortex Viper PST Gen 1. Never shot it with irons. When I got it, it had the rear sight damaged in shipping, so scope went on first. It’s not a scope or mount issue, been down those roads and eliminated those issues.

 

[Blowdowner]

I would love to have one... if I could find it. I know everyone says they are not needed, but I have one for my M1 Garand and absolutely love it. Makes the recoil better and saves the wear and tear the little it will get shot. I had no choice on that one. Factory plug went flying out during my first outing with that rifle...

There's some other company that makes a ported one.

 

[Choupique]

It’s not a scope or mount issue,

Adjustable gas plug, with the gas shut completely off, would be my next experiment.

 

[sniper20]

Adjustable gas plug, with the gas shut completely off, would be my next experiment.

I want one, not because it’s needed, but would be tunable and easier on the rifle in general. But finding them in stock is something else…

 

[sniper20]

Well, went out again to confirm the load. It has to be something with my scope/mount. Everything is still tight, but the load was zeroed the day before, but today, was shooting 1mil right and 1.5 mil low… and after adjustment, couldn’t keep a group on an 8.5x11 paper… shot 10 rounds, decided to try another 10 (and have been having ejection/extraction issues…) and the 2nd 10 rounds produced 2, 5 shot groups that were 1.25 MOA each… I don’t get it… the scope is proven, so not sure why it would be wrong and each and every bolt on the mount is tight.

 

[sniper20]

Went home and took the scope off… gonna try irons to see if it’s the scope or rifle.

When I took the scope off, I noticed there was one screw loose. It was the screw that is mounted on top, on the rear stripper clip guide. It was ¼ turn loose. I measured the distance from stripper clip guide, it appears to have moved after mounting. .135” on one side, .157” on the other. Still not enough to worry about.

But is the one screw that holds that tight enough to make it walk loose? Everything else is tight.

Also, on the magazine, look at attached picture. Is the round supposed to look like that feeding?

 

[Choupique]

has to be something with my scope/mount.

Id take it all apart, degrease everything, and reassemble with loctite 242 all over everything.

When you say the scope is proven, how? Semi autos can be pretty tough on scopes. Not using a lead sled?

 

[sniper20]

Id take it all apart, degrease everything, and reassemble with loctite 242 all over everything.

When you say the scope is proven, how? Semi autos can be pretty tough on scopes. Not using a lead sled?

I just took it apart and greased everything before taking out. I always clean all my weapons after each range trip.

Scope has been used for years on a few different rifles. And these are shot from a secure mount.

 

[Fireflyfishing]

Springfield mounts are no good. Pull it and the scope off and try shooting irons.

 

[sniper20]

Springfield mounts are no good. Pull it and the scope off and try shooting irons.

That’s my agenda for tomorrow. Gonna see if irons are any good.