Discussion in 'Ammunition & Reloading' started by Swaney109, Apr 24, 2010.
Whats the best 7.62 nato round for an AR-10?
Assuming you just want to buy ammo and not reload, Lake City M118 175 grain HPBT. This may be a bit pricey but you said the best and you also said NATO round rather than some other commercial load. If you are just looking for some decent but cheap shooting rounds, try the German made Dynamit Nobel rounds with the DM 111 encapsulated bullet that Sportsman's Guide is selling. These are 147 grain soft core NATO ball (berdan primed, non corrosive). The bullets are a cupronickel covered mild steel jacketed FMJ, but they will shoot fine and not harm your barrel. And they are dirt cheap.
Now can you shoot .308 out of a 7.62 barrel, like from an AR10? I was told you should not do that.
It should not be a problem out of an American gun. 308 is a higher pressure round, but that is the spec that most US companies build too. For use in a non US gun you should probable contact the manufacturer if you have questions.
Well it would be out of a DPMS AR10, classic style.
Either of the rounds I cited above should be fine in your rifle. The Lake City offering says "20 CTGS 7.62MM Long Range M118" right on the box. Being a military round it is made for 7.62 x 51 rifles but I have shot this also in a .308 varmint rifle. The DM offering says right on the box, "20 Patrone (20 cartriges), 7.62 x 51, DM 111, Weichkern". DM 111 is the bullet previously explained, Weichkern means Soft Core.
Also on the box is a circle with a cross (meaning NATO approved ammo) and a solid black circle (meaning ball ammo). These were manufactured in 94. Still good ammo, I shoot in my M1A.
I saw some of that German ammo on Cheaper than dirts website, even cheaper than on Sportsmans Guide. The barrel on the AR I'm getting is a 7.62, can you shoot safely .308 win out of it?
I don't know about the AR but I have been told that shooting .308 out of my G3 is bad JuJu. .308 is necked just a little bit different and in some cases (in the G3) the case is torn apart because of the gap in the headspace. Basicly my rule of thumb is this: If it's a military gun, use military or LE ammo . If it's a hunting or plinking rifle use commercial ammo.
No. The .308 is a much more powerful round and develops much higher pressures than 7.62 Nato. The rounds fit, but aren't safe.
Some AR-10's are marked .308 on the barrel and also probably in the lower and they are good to go for .308. You can also shoot 7.62 Nato in a .308.
I would never buy an AR-10 which wasn't chambered for .308.
Now, the opposite is true for AR-15. The 5.56 Nato is much more powerful than the .223. You can shoot .223 or 5.56 in a 5.56, but you can't shoot 5.56 in a .223.
Funny thing is that I had people tell me the opposite. I even have had a person say that you could shoot booth .308 and 7.62 out of a rifle that has a 7.62 barrel. Anyway I will just buy 7.62. I got a good hookup on some Lake City. Thanks
You can also prep .308 brass and re-load to 7.62 nato specs and shoot it. I don't though because 7.62 brass is cheaper and more available. You can re-load 7.62 Nato brass to .308 specs.
This thread prompted me to make a call to DPMS. They make their sporting rifles chambered in .308, but they also make the SASS, which I have, chambered on 7.62X51. Interestingly enough when I asked them if I could safety shoot .308 in my rifle chambered for 7.62X51 they said "no problem, but you don't want to shoot 7.62X51 in our rifles chambered for .308".
It's hard to say, but they can speak for their own rifles, assuming you got someone who knows.
Possibilities? The 7.62 has a slightly longer head space than .308 and if they are making their chambers real close tolerance, or are just worried about liability, then they could discourage the 7.62 in their .308. I've never seen a 7.62 that wouldn't easily chamber in a .308 though.
The real issue is that the 7.62 has a max pressure of 50,000 psi, and the .308 runs 62,000. I think much of the worry comes with milsurp guns with loose (normal for milsurp) chambers and the added pressure.
Since the .308 is slightly shorter than the 7.62 but not enough to make much difference, and since DPMS knows how strong their barrels and actions are, they would be the one's to make those claims.
Since the head space on 308 is less than 7.62, the 308 will always fit in the 7.62. The question is that over time, will the 7.62 take the added pressure of the .308? Apparently DPMS says theirs will.
I wouldn't take that as gospel for any other gun though.
Thanks, Gunner. That makes sense when you throw milsurps with looser chamber tolerances into the mix.
I believe the Gunner is indeed correct.
Keep in mind, the original question was what was the best 7.62 Nato round for an AR-10. Assuming (based on how the question was posed) the owner's rifle was chambered for 7.62 x 51, I told him either the M118 Lake City round or the surplus German Dynamit Nobel DM111 NATO round. Both of these are NATO spec rounds so if his rifle is chambered for the 7.62 x 51 NATO round, either of these (military) rounds should work fine.
Whether the .308 Win and 7.62 x 51 NATO are interchangeable in all respects is another question entirely, and the answer is no, not necessarily. Bottom line is they have different headspace dimensions and max pressures and while 7.62 NATO will generally work well with .308 Win chambered rifles, the reverse is not necessarily true due mainly to pressure issues.
That said, I have personally fired 7.62 x 51 NATO rounds (Lake City M118) in a .308 Win chambered bolt rifle with no problems and have fired max .308 Win handloads in a 7.62 x 51 chambered autoloader with no issues.
Never-the-less caution is always advised since firing military surplus 7.62 x 51 ammo or .308 Win ammo even in a properly chambered rifle is not always risk free--see for example http://thegunzone.com/m1akb.html.
This 7.62 vs .308 question seems to be one that gets asked on gun forums with some regularity (about every other day along with similar questions regarding interchanging .223 and 5.56 x 45), and has been answered in detail elsewhere. See for example:
My experience is the 6mmbr site is a reasonably good resource for such ammo related questions.
Gunner is correct,
The issue is with military surplus rifles and the fact that they were not designed to take 308 pressure.
As for the headspace....
I have a dpms 7.62 nato barrel and shoot both.
I have found that when you reload a 308 standard die set up will have more headspace than some of the military surplus in 7.62.
That being said the chamber on the 7.62 nato is large to accomidate dirt debri and a very dirty military weapon to still cycle.
The military does not reload so a stretched case from a loose chamber is not an issue.
Now if you reload this will cause case life problems for sure and if you use a 308 die to the instructions i have found you can be 15 thousands under on headspace (not good) this can result in case rupture after a few reloads.
So i use a hornady headspace gauge and adjust my die to 4-5 thousands under a fired case from that rifle wich will give you great case life and reliable feeding.
As for factory rounds any standard 308 loads should be fine since nato ammo is generally hot and headspace on a unfired nato round can be measure less than a factory 308.
Remember that mil brass is thicker to handle the looser chamber and increased expantion of the case.
That is why it is important to headspace the fired case on all military rifles and reload accordingly.
Just dont give your buddy the rounds to shoot in his gun as they will be custum to your rifle!
I must agree for the most part.
However, not all so called 7.62 x 51 military chambers are loose. For example Springfield Armory chambers their M1A national match and super match guns with tight "match" chambers. This can lead to some problems, especially since the M1A has a firing pin that protrudes slightly from the bolt face when the bolt is closed. If you chamber a reload that is not properly resized at the cartridge base the round will not seat all the way. However, because of the extra space needed for the protruding firing pin, the bolt will still close and still be in battery and will still fire when you pull the trigger. This poorly seated round creates a condition of excessive headspace and can cause a head separation when you fire--which can be disastrous--even to the point of destroying the firearm. Even if excess headspace is not sufficient to cause a head separation, when you fire the first round, the next round will be chambered and if it also does not seat properly the protruding firing pin can cause this second round to fire upon the bolt going into battery (ie without pulling the trigger), causing a "double" or two shots being fired automatically with one pull of the trigger. I had such a "double" happen to me with a scoped SA Super Match. I can tell you it was not a pleasant experience--and I really felt like a "knothead" afterwards.
Listen to Gunner on this, he's right
I use 147 to 150 grain surplus in my PTR 91 and HK 91 and get 2 MOA or less
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