Head space

[Dale]

when I went through boot camp at P.I. a way back in 1968, our rifle instructors told us we could shoot 308 in our M-14's or any other 7.62X51 nato ammo, except for linked machinegun ammo... said the machinegun ammo was loaded to higher pressures... dunno if this means anything or not, just thought I'd throw it out there...

[GRA]

when I went through boot camp at P.I. a way back in 1968, our rifle instructors told us we could shoot 308 in our M-14's or any other 7.62X51 nato ammo, except for linked machinegun ammo... said the machinegun ammo was loaded to higher pressures... dunno if this means anything or not, just thought I'd throw it out there...

I've heard this same thing before myself.  One of the reasons I considered a .308 in a configuration other than a bolt-action.

[beantown]

That would likely be the chamber that Black Hole Weaponry uses, they refer to it as "308B" :

http://blackholeweaponry.proboards.com/thread/850/308b-chamber

Thanks for the link. I should have known it was Black Hole Weaponry. And their dang barrels have polygonal rifling to boot. My wife is gunna kill me!  #bangshead

Edited December 27, 2015 by beantown

[unforgiven]

I have run linked ammo through my Rock River without issue.Sure was a PITA to get the links off.

[mrmackc]

I had a 250 round box of 7.62X51  think it was M85? that "fell off a truck" I was lucky, I traded it box ammo, links and all for 300 rounds of Federial.308 175 grain to a dealer that is a class III dealer.  

[survivalshop]

when I went through boot camp at P.I. a way back in 1968, our rifle instructors told us we could shoot 308 in our M-14's or any other 7.62X51 nato ammo, except for linked machinegun ammo... said the machinegun ammo was loaded to higher pressures... dunno if this means anything or not, just thought I'd throw it out there...

M14's & M1 Garands had a small problem with bending the operating rod with high pressure of the 308 /7.62x51 or in the M1 's case 30'06 , they produced special ammo for them , loaded lighter , if my memory is correct. You can have at it with any 308AR , no piston connected to the charging handle , so to speak.

[KeithB]

if the bolt closes on a Nato go gauge (1.6355) but not on a 308 field (1.638) you should be ok to use both.