M1A 7.62x51 or 308??

[Guest Rem_700]

I am pretty dumbfounded when it comes to figureing out the proper caliber for my M1A.It is no where marked on the rifle,and all the paper work I got with it,gives conflicting answers.My box says 308,but the manual says it was built to factory 7.62 NATO specs and then I have a little card that was attached to the gun that says this rifle has been headspaced to 1.631 according to GI spec and this rifle requires the use of GI mil spec ammo or good commercially manufactured ammo that meets GI specs.I am really confused.I am going to call Springfield come Monday morning.The reason I ask is because I thought they was the same,but my M1A didn't like the 308 is was running through it the other day.This is really the first time I had it out and was shooting Rem 150 MC UMC ammo.It had alot of FTF and a few FTE.But after shooting emptying the mag i loaded them back up and they all went off fine.The reason Im asking is because I went ahead and ordered some 7.62x51 nato ammo for my gun,and may I say quite a bit.So it has got me worried,did I order the wrong stuff?

[Smith]

If I'm not mistaken it is the same difference between 5.56x45 and .223. I'm pretty sure you ordered the right stuff as the regular .308 isn't loaded quite as hot. Probably the source of you're troubles as well as a head space issue.

[Guest Rem_700]

I was reading around the web and actually found out that the 308 has more pressure than the 7.62.I thought they was the same as the 5.56 and 223,but it is the other way around.Everything i've read says that the 7.62 has a thicker caseing than the 308.I feel pretty dumb for asking this kind of question.But why in the world wouldn't a rifle company mark there firearms with the correct caliber?

[Smith]

Well I did have that wrong. I was going from memory and it has been awhile.

[Guest Mugster]

7.62x51 and .308 winchester are roughly the same round. 7.62 spec is about a mid range .308 round.

In a self loader (m1 or m1a), they say stay away from hotter .308 ammo...not because the barrel can't take the pressure...but because it may mess up your op rod.

UMC .308 plinking ammo should be fine for an m1a. And mil spec 7.62 nato should also run fine. Stuff to avoid in a gun like that would be 180/190gr moose killing ammo.

As a footnote, 5.56 is extremely hot .223 Even though the case dimensions are similar. 5.56 pressure specs are above .223.

Military brass in .30 is sometimes thicker (and tougher) than the civilian equivalent. You only need to worry about that if you are handloading it.

[Almond27]

I would not use the 308 in the M1A as it may cause damage or worse and that is advice coming from a gunsmith I know. He told me the same thing about shooting 308 out of an Enfield

[Guest Rem_700]

I have only shot roughly 60 rns of 308 through the M1A,and it didn't like them too much.Those are the only rnds that I have sent down range in it.I can't wait to get some quality time with her!!

[Guest Mugster]

I ordered a case of this stuff to get me rolling on .308 for an armalite. Its out of stock here now, but if you can find it someplace else, its very accurate and consistent ammo and I can definitely recommend it:

http://www.the-armory.com/shopsite_sc/store/html/Lithuanian-308-Battlepack.html

I've also tested a little of the brand new south african (not suplussed) from wideners. Its pretty nice too. Not as accurate though.

[Guest Mugster]

I have only shot roughly 60 rns of 308 through the M1A,and it didn't like them too much.Those are the only rnds that I have sent down range in it.I can't wait to get some quality time with her!!

It may take the rifle a few hundred rounds a few cleanings to get running. UMC isn't the best ammo in the world either, but I believe it is safe to use in your rifle.

One of the mods here, Glenn, will probably chime in sooner or later. He shoots one of those m14 clones too. I'm sure he has an informed opinion.

[Guest Rem_700]

I ordered a case of this stuff to get me rolling on .308 for an armalite. Its out of stock here now, but if you can find it someplace else, its very accurate and consistent ammo and I can definitely recommend it:

http://www.the-armory.com/shopsite_sc/store/html/Lithuanian-308-Battlepack.html

I've also tested a little of the brand new south african (not suplussed) from wideners. Its pretty nice too. Not as accurate though.

That is the same stuff I ordered,ammoman.com has it for $549 a case with free shipping.I have a thread posted asking about it in the Ammunition thread.

[R1100R]

Century Arms has German 7.62 for 85.00 a 200 round batttle pack. A case is 425.00.

http://www.centuryarms.biz/proddetail.asp?prod=AM728B

[DaveTN]

In a modern rifle it makes no difference. (Based on your statements I’m assuming this is a fairly new Springfield M1A) If you had problems with .308 either it was the ammo or something is wrong with your rifle.

However.. junk ammo is junk ammo no matter what the caliber.

For range ammo I shoot Federal .308 Powershok from Wal-mart. It’s $12.99 for 20 rounds and its quality stuff. I don’t think you can order that quality at the same cost. As a matter of fact as soon as we can get together one of the forum reloaders and I are going to test this ammo against his reloads.

Or you can do this when Dicks runs the ammo specials they ran last week….

14.98 Winchester 150 GR. Power Point (X 3 boxes limit) 49.32

14.98 Remington 150 GR. Core-Lokt (X 2 boxes limit) 32.88

Total $82.20, $25 in mail in rebates = $57.20 for 100 rounds.

Again… I can’t beat that online.

Edited November 16, 2008 by DaveTN

[Guest Rem_700]

I just got off the phone with Springfield and they told me that all thier M1A's are chambered for 308,which allows you to shoot 7.62x51.She said that if the gun was chambered for 7.62x51 that you could not shoot 308 out of it.

[John Wall]

The main difference between the 308 Winchester and the 7.62 Nato is the headspace of the firearm. Chances are, if your firearm were checked, you would have more than the 1.631" chamber. This is only .001" more than the minimum specs for the commercial 308 round.

Without getting into very small numbers, most all modern 308 rifles have 7.62mm chambers. My Ruger All Weather and Browning A-Bolt II have identical 1.634" chambers. This is actually excessive for a commercial 308 chamber. This is 7.62mm spec. Both were bought new, and are typical.

This is good. The 7.62 chamber is a little looser than the 308. The person at Springfield Armory has it backwards. I once had a Remington 40-X with a 1.631" chamber. It would not chamber some military ammo, including Lake City Match. :^(

For your M1-A, use ammo with bullets lighter than 180 grains and you will be fine. There is little reason to use expensive commercial hunting ammo in these guns.

Also, the "Light Magnum", "High Energy", and such higher velocity loads should not be used.

I shot a S. A. M1-A Natl' Match rifle often enough at one time to need an annual rebarreling.

These guns do their best under 300 yards with the 155 gr Sierra Match King, up to 600 yards with the 168 gr match bullet. Longer ranges will do best with the 175 gr SMK.

Remember, the 7.62 is not a Magnum. At long range, this round drops many feet and the wind will push it around quite a bit.

The 223/5.56mm issues are different. The chambers are about the same, but the throat on the 5.56mm is longer.

My Browning A-Bolt II Varmint is marked "223/5.56mm" and has a faster than normal twist. It will shoot in the high twos with the 60 gr Hornady V-Max.

Reloading the M1-A is easy and straightforward. Accurate 2520 powder and the 168 gr Match bullet with most any non magnum primer will work well. CCI may work better in military brass. I use 44.7 gr with commercial brass, and 42.5 gr with the heavier military brass. Load the round to 2.810" Over All Length (OAL)

Military brass will work well in your rifle up to 300 yards. It is actually made to closer weight tolerances than commercial. Neck runout is a little more in G.I. brass, but out to 300 yards, it works well.