7.62x51 in a .308

[M1A Rifleman]

The other factor not discussed for an M1A is that it also depends if the rifle has a GI barrel or the commercial barrels that are now being installed as the chamber dimensions are different. For the older M1A's, Springfield recommends GI or Military spec ammo. 20+ years ago this was difficult to get and so your choices were limited to the commercial stuff. Port pressures for the M1A are still an issue to watch as over pressure at the port can cause the opp rod to return with too much force. I think this may be more of an issue with handloads. I believe the worry with commercial ammo in a longer GI chamber is the potential for the brass to lengthen to the point of a case head separation. I had this happen with Remingtons UMC brand one time - 3 separations out of 20 rounds and also had several rounds keyhole.

[MR.R]

hmm not sure of the age of the rifle, got it from a calgunner last year. serial #200xxx if that helps. no markings on the barrel..

[M1A Rifleman]

hmm not sure of the age of the rifle, got it from a calgunner last year. serial #200xxx if that helps. no markings on the barrel..

If its not chrome lined its most likely not GI. Marking can be seen once you pull the opp rod back as they are visible just under the hand guard and stock. GI Markings might look like SA, or HR, or TRW, or WIN, they will also have a date stamp 2/66 or 4/68, etc. GI barrels will be dates in the 60's or 70's. There will also be a drawing # 714652..., however commercial parts may also have the drawing number.

[MR.R]

thanks for the info!! i really dont think the rifle is that old, i know it is the standard model with the breakup camo stock. pulled the upper handguard has
Geneseo IL .308 on the barrel.

[MR.R]

ok pulled the stock.7267064-2 with a SA under the numerals

[M1A Rifleman]

ok pulled the stock.7267064-2 with a SA under the numerals

Not enough info to help. The the 7,,, is the drawing or part number, but like I said these are also on some commercial parts. The Genesco Ill mark is Springfield's Commercial mark.

My rifle is a 1990 vintage with a GI barrel. Springfield also marked my barrel on the underside just forward of the gas nut. Verify if it is chrome lined as without seeing it this is the only way I could confirm if its GI or not. SA stopped installing GI barrels around 1997+/-.

[Jpach]

I learned about this difference AFTER I bought my Remington R-25. And although I can shoot 7.62 in my 308 rifle, it's hellaciously inaccurate. While I can shoot 1 inch groups at 100 yards with dollar-per-round 308 ammo, inexpensive 7.62 ammo shoots 6 inch groups. Disappointing.

Thats the opposite of my .308 AR haha. With FGMM I was getting like 4-5 inch groups and with Aussie milsurp I get like 1.something inch 10rd groups. Its just stupid. But then with hand loads the groups are sub-moa.

Everyone I know that shoots Aussie surp seems to love it. Ive seen a sub-MOA 10 or 5(cant remember) shot group at 100 that was like .75 MOA from a 5R (IIRC) with Aussie ball. That ****s awesome

[MudCamper]

Thats the opposite of my .308 AR haha. With FGMM I was getting like 4-5 inch groups and with Aussie milsurp I get like 1.something inch 10rd groups. Its just stupid. But then with hand loads the groups are sub-moa.

Yours is likely chambered for 7.62. I know that DPMS, who makes my R-25, makes both chamberings. Mine is 308 however.

Everyone I know that shoots Aussie surp seems to love it. Ive seen a sub-MOA 10 or 5(cant remember) shot group at 100 that was like .75 MOA from a 5R (IIRC) with Aussie ball. That ****s awesome

I'll look for it and give it a try. I've also got some of those South African battle packs of 308 to try out.

[Jpach]

Yours is likely chambered for 7.62. I know that DPMS, who makes my R-25, makes both chamberings. Mine is 308 however.



I'll look for it and give it a try. I've also got some of those South African battle packs of 308 to try out.

You know what, I was never really all that jacked over the SA stuff. It does seem to be a tad hotter than the Aussie stuff though. Oh, by the way, IIRC the reason why I wont try the SA stuff in my .308 AR is because it voids the DPMS warrantee and therefore would probably void the warrantee on the R-25

[high_revs]

I wanted to pass on what Noveske told me also. Pretty much, you can shoot a .308 into their 7.62x51 N6 upper. No safety issues but there *might* be functionality issues, i.e. hard ejection, effects on brass, etc. They informed me that they tested on hotter weather (like Afghanistan type heat) which was suppose to bring up the pressures more and it worked out fine. But oddly, they said some "hotter" ammo have more functionality issues. Ones that Noveske referred are Federal Gold Medal Match (which says on their website .308/7.62x51). I've contacted others and they've successfully shot .308 in a 7.62 rifle also, granted these are newer rifles. Noveske also said try different ones since (like the saying goes) not all rifles like the same ammo.

[MudCamper]

IIRC the reason why I wont try the SA stuff in my .308 AR is because it voids the DPMS warrantee and therefore would probably void the warranty on the R-25

DPMS says shooting ANY 7.62 ammo voids your warranty: http://www.dpmsinc.com/forum/posts.aspx?postID=2271

The really weird thing about that post is, it says exactly the opposite of what everyone else in the industry says about 308 vs 7.26x51. They say that you can shoot 308 in a 7.62 but not 7.62 in a 308. This adds much confusion to the issue. I think the reason they say this is that they build their 7.62 chambers with 308 pressures in mind, but since 308 chambers can handle 7.62 they didn't do anything different to these. But then because of this they come out with this backwards warning. Crazy confusing.

ETA: Oh, and Remington's crappy warranty is only for 2 years anyway.

[1 SIG fan]

Just got off of hold with Savage. THey said in the Model 10 .308 (heavy Varmint) you CAN shoot the 7.62x51 surplus ball. Good to know

[westcoastr]

good info on 308 vs 7.62:

http://carnival.saysuncle.com/002453.html

[MudCamper]

good info on 308 vs 7.62:

http://carnival.saysuncle.com/002453.html

Good article. Thanks.

[bigstick61]

Here's an article I found called "The Truth about 7.62X51mm NATO and 308 Wnchester"

http://home.comcast.net/~ehorton/The%20Truth%20About%20308%20Win%20and%20762%20NATO.pdf