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 DPMS 308 Win and 7.62 x 51 Barrel question
sterling18  [Team Member]
4/9/2011 1:43:38 AM
Senior moment. But for the life of me, I can't remember the answer. Can DPMS 308 Win barrel run 7.62 x 51 or only 7.62 x 51 barrel run 7.62 x 51 and 308 Win?

I was asked if the LR308 run 7.62 x 51 surplus in it.

Thanks
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DnPRK  [Team Member]
4/9/2011 12:05:00 PM
There is a minor difference in headspace and throat lengths with 7.62x51 being longer. But the real difference is the potential pressure curve difference between mil 7.62x51 (medium burning rate powder with "moderate" pressures) and commercially loaded 308W with heavy bullets and slow burning powder (with "high" pressures). 20 years ago, the later was common in hunting loads in an attempt to duplicate 30-06 loadings. At that time, the market was bolt action hunting rifles, not gas-operated rifles. For a gas-operated rifle, slow powders and heavy bullets usually cause extraction problems.

Some LR308s are known to have tight chambers...too tight to allow some foreign-made surplus ammo to fit. So the answer is "maybe". Also remember that many foreign armies who used 7.62x51 also had rifles with adjustable gas systems. They could adjust the gas system to shoot manufacturing lots of ammo with wildly different pressures (poor quality control during ammo manufacture).
slowtrigger  [Team Member]
4/9/2011 2:01:25 PM
from what I have read the 308 has the higher pressure, so it should be safe shooting 7.62 X 51 in 308 win chambered weapon. I know I shoot 7.62 X 51 out of the rifles I have chambered for 308win. and have never had a problem or have anything blow up in my face. ......yet (knock on wood)

308 Winchester - 62,000 max .......................7.62×51 max is 50,000 psi


read this http://www.thefirearmblog.com/blog/2007/09/03/308-winchester-vs-762x51-nato/
and do search that covers more than 1 web site. this question has been debated for sometime. and the answers seem to change from one site to the next. .

but I would go check DPMS web site warranty info.. to make sure what they will cover under warranty
Rebelwolf  [Member]
4/9/2011 6:53:43 PM
Originally Posted By sterling18:
Senior moment. But for the life of me, I can't remember the answer. Can DPMS 308 Win barrel run 7.62 x 51 or only 7.62 x 51 barrel run 7.62 x 51 and 308 Win?

I was asked if the LR308 run 7.62 x 51 surplus in it.

Thanks


It is safe to shoot the nato round in the .308 chamber. Whether it will feed and extract well is another issue altogether. DPMS has a reputation for a tight .308 chamber, good for accuracy but sacrifices some reliability. Good quality nato should be no problem but DPMS will likely tell you not to use the nato round in the .308. Again not a safety issue just may not feed well.
sterling18  [Team Member]
4/10/2011 1:11:15 AM
thanks, i'll pass it along.
Cabinetman  [Team Member]
4/10/2011 9:05:00 AM
I've ONLY shot 7.62 x 51 surplus through my DPMS LR308 with an 18" bull barrel exclusively since I've owned it almost a year and a half now. The ONLY time I had ANY issue was when I first got it.

The first thing I did was to headspace the rifle with my gauges. I have all three. It spaced perfectly. Then I removed the bolt and dropped in a surplus round. It dropped firmly into the chamber and sat perfectly. I was good to go.

Then I ran my first 19 rounds through it without a hiccup. The second mag, however, I had one round that balked on extraction. I cleared it and checked the chamber but didn't find anything amiss. I ran the rest of the mag through it and since then have not have one issue at all. The chamber was tight to be sure but, since running probably 800 rounds through it since then and cleaning a few times, it runs like a swiss watch. No issues at all. Some guys have reported uber tight chambers and extraction issues but mine has run perfectly.

I've run just about all the surplus on the market through it, too. I bought the rifle for the specific purpose of shooting up my large stash of surplus. At the time I ordered it, I wasn't even aware of the two 'models' offered: 308 win or 7.62 x 51 because it wasn't mentioned in the literature from the supplier. The one got was marked .308win but, having build my M1a to match quality and having owned and run every one of the 7.62 x 51 military rifles on the market, I was confident that I'd have no issues and I was correct. Of course DPMS says in their literature that I've voided my warrantee by not shooting only commercial ammo in a .308 barrel. I accepted this responsibility on my own and have never looked back. I suspect they say this because they don't want rifles returned to them that have super tight chambers causing issues with surplus ammo.

BTW, accuracy is amazing with this rifle, even with the wide variety of surplus I've run.

Rome
sterling18  [Team Member]
4/10/2011 11:26:36 AM

Originally Posted By Cabinetman:
I've ONLY shot 7.62 x 51 surplus through my DPMS LR308 with an 18" bull barrel exclusively since I've owned it almost a year and a half now. The ONLY time I had ANY issue was when I first got it.

The first thing I did was to headspace the rifle with my gauges. I have all three. It spaced perfectly. Then I removed the bolt and dropped in a surplus round. It dropped firmly into the chamber and sat perfectly. I was good to go.

Then I ran my first 19 rounds through it without a hiccup. The second mag, however, I had one round that balked on extraction. I cleared it and checked the chamber but didn't find anything amiss. I ran the rest of the mag through it and since then have not have one issue at all. The chamber was tight to be sure but, since running probably 800 rounds through it since then and cleaning a few times, it runs like a swiss watch. No issues at all. Some guys have reported uber tight chambers and extraction issues but mine has run perfectly.

I've run just about all the surplus on the market through it, too. I bought the rifle for the specific purpose of shooting up my large stash of surplus. At the time I ordered it, I wasn't even aware of the two 'models' offered: 308 win or 7.62 x 51 because it wasn't mentioned in the literature from the supplier. The one got was marked .308win but, having build my M1a to match quality and having owned and run every one of the 7.62 x 51 military rifles on the market, I was confident that I'd have no issues and I was correct. Of course DPMS says in their literature that I've voided my warrantee by not shooting only commercial ammo in a .308 barrel. I accepted this responsibility on my own and have never looked back. I suspect they say this because they don't want rifles returned to them that have super tight chambers causing issues with surplus ammo.

BTW, accuracy is amazing with this rifle, even with the wide variety of surplus I've run.

Rome

Good to know, btw, would you go longer on the barrel or 18 is GTG? Thanks,
Cabinetman  [Team Member]
4/10/2011 3:51:14 PM
If I were to do it all over again, I'd go with a standard barrel and forego the HB. It would save about a pound. The rifle, now, all up and ready to fire is about 12 pounds and I'd like it to be 11 or 10 but I can't go with a skeleton stock here unless it was fixed (no folders or adjustables allowed here in CT) and the shroud could be lighter.

The 18" barrel affords excellent accuracy. I would not go shorter nor longer unless you were a bench rester. This rifle is my zombie killer and the only mod I've made was to install a Geissele trigger. That made a tremendous difference in the accuracy, too. Shoot it and you'll be smiling all day long. The 18" barrel also balances beautifully right at the mag well so the rifle is easy to handle.

Seriously, I would not change a thing. DPMS makes an excellent product for a rifle you'll want to haul in the field. It's realiable, super accurate, easy to maintain, and would be good to 600 yards easily, probably more.

Rome
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