Years ago military ammo was thought to be bad to shoot out of civilian guns.  I was in the Air Force and had access to 7.62 and 5.56.  We were constantly told to never use 7.62 in our 308 hunting rifles as it would ruin the barrels.  Now, years later, I think they told us that to prevent us form ripping off the government by taking it home.  The 5.56 was an exception because at the time all AR's were made buy one company, Colt.  So military and civilian AR's used the same barrels and could use the same ammo.  Now I have a large amount of linked 7.62 that was originally for a M60 machine gun.  I'd like to use it in my SCAR17 but I keep hearing my military range officer telling me it could ruin my barrel.  Thoughts?

A hold over from surplussed WWII ammo that was corrosive.

You think they were lying to you, to keep you from stealing government property?  Interesting.

Generally speaking, as long as the rifle you are shooting is chambered for the round, you shouldn't have a problem.  You do run into odd power and pressure curves for some types of ammo, usually foreign made, but that usually manifests itself as a reliability problem long before it would or could cause damage to your gun.  Chances are, if you tried running military 7.62 through a standard hunting rifle, you would find it difficult to extract the fired rounds and you would not want to continue using it anyway.  Stuff like that.

 
 Actually he does!  He's correctly concerned about headspace differences between longer 7.62 x 51mm NATO spec. cartridges, and shorter 308 Winchester cartridges.  There are also significant differences (or there can be significant differences) between both the ignition and operating pressures of 7.62, and 308 cartridges.  Unless a shooter knows the exact headspace of his 308 chambered rifle, as well as the amount of leade in front of that chamber it would be foolish to simply start using 7.62 x 51 ammo in a commercially cut 308 barrel chamber.  

SAAMI 308 headspace = 1.62-1.63".  NATO 7.62 headspace = 1.6355" AND the NATO cut chamber also has a longer leade in front of it.  

Years ago this situation was a real problem for Springfield Armory with their early M14 rifles; and it is, also, the reason why SA has (1) issued measured headspace notices with each new rifle, has (2) modified their chamber/leade dimensions, and (3) now stamps their barrels as 308/7.62 instead of only 308.  Be aware that there are still plenty of older 308 rifles out there that remain unsafe to use with 7.62 ammo.  

READ YOUR BARREL STAMP.  WHAT DOES IT SAY?  IF YOU'RE UNSURE, MEASURE THE HEADSPACE AND LEADE ON YOUR SCAR-17.  (What you don't want to see is, '308 Win.'; and a call to FN/USA MIGHT ALSO BE IN ORDER.)  

According to THIS it appears that you should be, 'good-to-go'.

Military ammo is not going to hurt a SCAR.

+1

Thousands of military surplus 7.62 NATO rounds fired, and my M14s continue to run like sewing machines.

Thanks, I was 99.9% sure it was ok but that .1% is what kept me up at night (not really).

 

 
Yeah, guys, that's what I said; BUT, neither is it the main point to what I posted.  What I posted says a lot more than something as myopic and inane as, 'Military ammo is not going to hurt a SCAR.'  Additionally I gave some of the history as well as other important reasons, 'Why' that instructor actually does know what he's talking about, AND should continue to give out the same advice.  

Does anybody know of a single rifle destroyed by the use of non-corrosive military ammo?  I don't.

The point is, you were defending the idiot that claimed it was going to ruin the barrel.  It won't ruin the barrel of even a hunting rifle.  It might cause reliability problems, and the accuracy might be shit, not to mention there is no reason to hunt with ball ammo,  but there are no pressure concerns.  The information you posted is actually backwards.  There were problems shooting commercial 308 loadings through M14 style, and other type military rifles, because they were not designed to handle commercial spec pressures and/or pressure curves.

Think about what you said.  If they used to stamp their barrels 7.62 and currently stamp them 7.62/308.  That means they started manufacturing the rifles so they could shoot 308 in addition to 7.62.

The SCAR was made for the military, of course it's going to be fine with military ammo.

You shouldn't people when you missed the important difference in chamber pressure of the two rounds that might actually cause a serious issue.

Bottom line is 7.62x51mm is fine in .308 rifles. .308 in 7.62x51mm can be a problem in certain rifles particularly older ones. The OP is asking about 7.62x51mm in a modern rifle that is was designed to be chambered in 7.62x51mm. There is no issue there (aside from the usual caveats with any ammunition in the rifle it is chambered for).

In the Army we were told during an in-depth rifle class that if it's the end of the world and we're fighting on our own turf, etc; to never use .223 in our rifles unless we absolutely have to.

Likely so we wouldn't be so willing to use civi ammo, which you never know if it's a crap reload or meant to blow up the gun by packing longshot or something in it.

AF probably generally had no idea what they were talking about though, or didn't want you to steal. Wasn't it an AF sgt type that was caught 'stealing' several cases of 5.56? Sadly, all it was is ammo that would ahve been tossed, so he took it. Some AF boyscout reported. Sucks for that guy.

Delink that ammo and enjoy shooting your SCAR with it.  I save my M118LR for combat loads and accuracy shooting.  Just blasting up close and running drills I have no problem delinking M80 ball off belts.  


I've also ran M80 and M118 out of my commercial Mauser 98 and Springfield Armory SAR-48 Bush rifle both chambered for .308 .


CD

Except the 5.56/.223 pressure issue is backwards from the 7.62/.308.  Any rifle chambered for 5.56 can shoot the .223, although accuracy might suck, depending on your twist rate and bullet weight.  But there are those who say the reverse is not true, due to higher 5.56 pressures and tighter .223 chambers.

no: stop spreading the wives tale

just stop

For all the 308 vs 7.62 its a holdover from CUP to PSI there is not a direct correlation.


If you look at any "recent" testing there is not a pressure difference.


This ongoing BS gunshop rumor has been perpetuated by mainly the m14 guys where 308 pressure curves cause problems in the m14s. In any other rifle its a non issue. Its also a non issue in the m14 AFA safety, but cycling that POS lead some to belive OMG 308 pressure is deadly.