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Help: m1a gas system edition

748 Views 13 Replies 10 Participants Last post by  tailgunner
So, this might be the wrong place for this, but I thought I would reach out to the brotherhood.

I have a Springfield National Match m1a. The thing is a tack driver but wont cycle reliably.

I took it to a gunsmith who claimed that for some reason m1as can sometimes require higher grain rounds. He messed with it some, with some success.

So here is what I have noticed. If I shoot 7.62 or 308 in the 150s grain range it basically doesn't cycle. If I run 160s grain 308 it cycles maybe 50 percent of the time.

I am thinking of just running heavy 308 through it. So how high can you safely go with an m1a before you, say, mess up the op rod?

Any other thoughts on the issues I am having?
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I have a little experience shooting the M1A. Everything from 147 NATO Ball to 175 BH should work. Since its lighter loads that causing problems I would start with making sure the gas plug insides and piston is clean. Leave no solvent or oil on these parts. Also might check to see if it does have a Shuster or similar gas plug. These are vented to allow shooting higher pressure rounds like 180's etc. Get a NOS GI plug if possible, and the correct tools to take the plug out while holding the gas cylinder against the rotation. If the rifle has had the Front band fixed to the gas cylinder by screwing it on, the gas cutoff spindle will be immovable in most cases. Gas piston might be undersized also from too aggressive "polishing" . One more thought would be checking the op rod spring and spring guide. Look for gunked up dried grease on the spring, guide and in the channel it rides in the op rod. If the "gunsmith" was familiar with M14 operations and specs, he would have checked these things. Brings you back to maybe the ammo. Some ammo, no matter how nice it looks, is weak and sucks. If it isn't brass cased, and you would not drink water from the faucet where it was produced, find something else. Good luck on a usually fantastic shooting rifle.
2 more thoughts. Dicked magazine. Try hand cycling 5 rounds , outside and pointed in SAFE direction
. Like ammo, some mags are just trash. I was given 2 nicely finished blued unmarked mags one time that would cause short stroking. Didn't take any time to figure what was wrong, just lay them on the berm and proceeded to shoot them up. Also check to see if your op rod spring is too long. I saw a rifle that had either an M1 spring installed or some after market spring. It was so tight I could barely seat a magazine. It was several inches longer than a GI spring. They had short stroke problems until they swapped for a GI spring.

Good luck
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