7.62 Nato in my M1A?

[Hecklerusp45]

I have a M1A that I had built using a Springfield receiver and a Kreiger barrel. When I got the barrel it had been short chambered. I sent the barrel, receiver, and bolt to Match Service Works to have the barrel chambered and installed, and had the headspace taken care of. I have always used my reloads in the rifle with great results. Recently I got a quantity of 7.62 Nato ammo (still on M60 belts). Would that ammo be safe to shoot in my M1A?

[nf1e]

What headspace did you have your Kreiger reamed to? If you are 1.632 or more, you should be fine.

[m1ashot]

Shoot reloads measure case with Hornday HS guage. Them measure 7.62x51 loaded ammo. You need to be .003 shorter mi numn do this to be safe. M1as are bombs in your hand and takes extra caution

[StockDoc]

Ask the person who headspaced the rifle. The reason I say that is some will say you could shoot either, still other will say different. At least asking the person who did the work, will give you some comeback if the answer was wrong.

[Richard H Brown Jr]

Of course if you have a source for the 7.62mm Nato Go/No Go gauges, disassemble the bolt to remove the ejector and see if the GO gauge locks up in the chamber.


R. H. Brown

[StockDoc]

I have 5 rifles that I chambered with a PTG finish reamer in .308 win. $ of the Rifle are Semi auto, 1 Garand and 3 M14's (FA Receivers) and 1 Bolt in 308 (Mauser Rec.) yet the semi auto rifles will not chamber a 7.62x51 American Eagle round. But the Bolt gun will. Same reamer and gages. Why, I have no idea. so I just stick with the 308. BTW this was off the shelf ammo. on the reloads, it will shoot both, and I use a 308 case to set the die. So the answer, It depends.

[Col. Colt]

There is headspace and then there is Throat Length. If the gun will not fully chamber a 7.62 NATO spec round, I would assume it is NOT a good idea to shoot NATO ammo in it. Both 7.62 NATO vs. .308 Winchester and 5.56MM vs. .223 Remington have the same potential issues. The small/"Match" Commercial chamber does not allow for the "leade" (throat) length that the NATO/military rounds are designed for. Either get the chamber AND THROAT lengths corrected, or stick with Commercial sized .308 ammo. Just my .02. CC

[Hecklerusp45]

Ask the person who headspaced the rifle. The reason I say that is some will say you could shoot either, still other will say different. At least asking the person who did the work, will give you some comeback if the answer was wrong.

I think that you are right on this, so I asked the person who headspaced the rifle and he said that if I use the good quality ammo (he said use Lake City ) that there should be no problems.

[Col. Colt]

My concern remains that you may have a "tight chamber", due to being setup as a match gun. I know Kreiger NM Heavy M14 barrels generally get a pretty tight NM spec chamber. And throat length can affect pressures if the bullet is right against the lands upon chambering.

All GI Ammo is "good quality". I would definitely get it gauged by someone who understands M14/M1As. Barring that, watch carefully for pressure signs in your fired cases.

There are quite a few posts on this exact subject over at M14 Forum, if you wish more information. Here is one of many - it is definitely an opinionated topic!:

http://m14forum.com/m14/111291-headspace-commentary.html

CC

[lonegunman762x51]

I've never seen USGI ammunition that would not work in a USGI gun. If the gunsmith your hired did not chamber it for 7.62 x51 then what did he chamber it for?

[Hecklerusp45]

It is not a USGI gun, if it were it would be a M-14. I have a M1A. They can be chambered in 308 Winchester or 7.62 Nato. They are not exactly the same. That is why I was wondering if the ammo I had was safe.

[StockDoc]

It is not a USGI gun, if it were it would be a M-14. I have a M1A. They can be chambered in 308 Winchester or 7.62 Nato. They are not exactly the same. That is why I was wondering if the ammo I had was safe.

M1A is a copyrighted name used by Springfield INC. The rest are M14.
can be found just as cheap at the gunshows
I really don't see a purpose to use the 7.62, 308

[Hecklerusp45]

M1A is a copyrighted name used by Springfield INC. The rest are M14.
can be found just as cheap at the gunshows
I really don't see a purpose to use the 7.62, 308

The only reason to use the 7.62 was because I had a bunch on had, did not buy it for the M1A, just had it fall into my lap. I am not trying to argue what is and what is not a M14, just want to be safe.

[StockDoc]

understand, sometime the force of the bolt will move the shoulder back just enough to work try it.

[nf1e]

Get your headspace checked by someone that knows what they are doing. Your gunsmith should be able to give you that information. All 7.62 nato and .308 cartridges are produced with the same exterior. In fact , they are all loaded with .308 dies. It is the chamber of the rifle itself that can cause a problem. Most SAI rifles were headspaced to 1.631. I like to set headspace on my M14 type rifles to 1.620 - 1.633. As long as you keep your bullet weight less than 180 gr. you should be good to go. I like to load my ammo to .003 to .005 less than my chamber headspace. The NATO chambered rifles are also generous on headspace and in the diameter of the chamber to allow for dirty ammo , 1.633 to 1.640. It is not difficult use a reamer that will allow you to set the headspace and throat as a unit.