[Aging Disgracefully]

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?

 

[Aging Disgracefully]

Addendum:
I am thinking about buying a couple of boxes of Black Hills Ammunition 308 Winchester 175 Grain Match to test this theory. If it doesn't work can I safely run it through my 17s? Never went that high before with the 17s.

 

[nelly105]

i ran american eagle through my m1a scout. both the regular .308 and the special m1a 7.62x51. 165/168gr.

 

[Aging Disgracefully]

It is interesting you say that. I have a SOCOM II as well and it just eats everything. I am thus shocked by my experience with this national match m1a.

 

[Talhoffer]

I've had to run these before in M1A's, mostly when running the M1A suppressed.

http://www.brownells.com/rifle-part...-system-prod20456.aspx?avs|Make_3=Springfield

One line of ammo you don't want to run in your M1A is Hornady Superformance, it will bend your op rod due to the higher pressure they run in it.
168gr is about the heaviest I run in my M1A's.

 

[Grinder]

It should run with almost any 145-175 grain load.
Something is amiss.
Check for a modified gas piston (used for heavy loads)

 

[Canyon Man]

I've run my share of M1a's, and I've never had any trouble running any type of ammo. I mostly ran 150 grn, and tried to stay aaway from 180 grn, but had shot it on more than a few occasions. I never bent an op rod. But I've been told it's possible. The only time I ever had trouble was when I sprayed some kind of foaming bore cleaner in the barrel (don't remember the brand, too long ago). And yes, after I did it I realized that was just stupid of me. It clogged the gas port and wouldn't function well until I cleaned it out. Perhaps a burr in it ? Perhaps, just perhaps the wrong spring, guide rod problem...I'm sure you've checked all that...Only other thing I can come up with is the National Match barrels have a REALLY TIGHT chamber. Even a little sand on the action will lock them up. The standard barrels are much more forgiving with sand, and I'm wondering if you are having trouble with casings getting stuck in the chamber. Perhaps a reaming of the chamber if by chance it's a little to tightly toleranced. I'm afraid I've posted this uselessly, as it's kind of reaching out there a bit...but something just seems amiss. It's possible you'll bend your op rod with higher pressure loads, but typically, M1A's fire everything from my experience. I've owned about eight or so I'd guess. And PS...the one made in China was the softest shooting 308 without a muzzle brake I'd ever shot to this day. The guy I sold it to still won't sell it back to me at double what I sold it to him for.

 

[M1P90]

I'd say disassemble the SOCOM and the NM and compare the gas systems and ports. There could be a burr or the hole might be not drilled out completely. There has to be some drag somewhere check all op rod grooves and even the bolt head. Sometimes the bolt head needs to be worked in so it doesn't catch when it locks in the chamber. Good luck figuring this out. :-o

 

[Aging Disgracefully]

I've run my share of M1a's, and I've never had any trouble running any type of ammo. I mostly ran 150 grn, and tried to stay aaway from 180 grn, but had shot it on more than a few occasions. I never bent an op rod. But I've been told it's possible. The only time I ever had trouble was when I sprayed some kind of foaming bore cleaner in the barrel (don't remember the brand, too long ago). And yes, after I did it I realized that was just stupid of me. It clogged the gas port and wouldn't function well until I cleaned it out. Perhaps a burr in it ? Perhaps, just perhaps the wrong spring, guide rod problem...I'm sure you've checked all that...Only other thing I can come up with is the National Match barrels have a REALLY TIGHT chamber. Even a little sand on the action will lock them up. The standard barrels are much more forgiving with sand, and I'm wondering if you are having trouble with casings getting stuck in the chamber. Perhaps a reaming of the chamber if by chance it's a little to tightly toleranced. I'm afraid I've posted this uselessly, as it's kind of reaching out there a bit...but something just seems amiss. It's possible you'll bend your op rod with higher pressure loads, but typically, M1A's fire everything from my experience. I've owned about eight or so I'd guess. And PS...the one made in China was the softest shooting 308 without a muzzle brake I'd ever shot to this day. The guy I sold it to still won't sell it back to me at double what I sold it to him for.

This is good: I had not thought of the tight chamber issue.

 

[H2O MAN]

Does your rifle pass the tilt test?

If you turn the gas valve OFF, you can shoot the heavier loads without issue.

 

[Buffman]

Have you verified gas port alignment?

Shimming the gas cylinder and gas port alignment: A "How To" - M14 Forum

 

[Fröman]

Heavy loads will bend your OpRod if you don't use a vented Schuster gas plug so be careful. Also check your twist rate. Unlike our magical SCARs the loose twist of an M14 barrel will group like crap with ammo that's too heavy.

 

[H2O MAN]

You really don't need an adjustable gas plug, all you need to do is turn off the gas valve when shooting heavy projectiles.

My M14s have a 1:10 twist rate, and group heavier projectiles tightly :?

 

[tailgunner]

AD,
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