This is a discussion on 7.62x51 vs .308 Winchester within the Ammunition forums, part of the M14 M1A Forum category; Hi, I'm new to this forum and I need the following info. First I'm seriously thinking about getting a NIB M1A (don't have one now). ...
Hi, I'm new to this forum and I need the following info. First I'm seriously thinking about getting a NIB M1A (don't have one now). Here's are my questions.
1. I understand all Springfield M1A receivers are stamped 7.62 x 51, is that correct?
2. Can I shoot commerical .308 Winchester in an M1A, stamped 7.62 x 51, safely?
3. Will M1A Trunion safely handle the higher pressures of commercial .308 vs Milsurp 7.62 x 51?
4. I understand 7.62 x51 (Nato Milsurp) has a chamber pressure of about 49,0000 PSI vs commerical .308 Winchester of about 62,000 PSI, is that correct?
5. I understand the cartridge chamber of a 7.62 x 51 is slightly different than that of a .308 Winchester, is that correct?
My plan is to shoot only commercial .308 Winchester ammo, can I?
As far as the ammo question, the answer seems to be "yes, but......."
There are commercial loads that it is not considered safe to fire through an M-14 type rifle. The very heavy loads (175 to180 grain and anything considered "light magnum") can cause excessive pressure (you could turn off the gas at the spindle valve and theoretically shoot whatever you wanted, but then you would end up with essentially a straight pull bolt action rifle).
The M1A is headspaced by all accounts between .308 and 7.62 NATO. .308 Winchester out of a 7.62 NATO chamber is generally considered OK.
There's more info available than I can realistically put in this post. This topic has been discussed numerous times, so get into the search feature and simply look and read.
Well what's stamped 7.62x51 or 308 Winchester doesn't carry the weight or the difference some AR-15 stamping do. The pressure difference is little to none. The pressure measuring methods are different and can't be directly compared to each other. Springfield Inc. says 308 Winchester ammo with bullets under 180 grains is safe. The real difference, besides bullet weight, is the amount of gas at the gas port which changes with the type of gun powder used. Some commercial 308 ammo may produce too much gas for the M14. Some commercial ammo is made to function properly in the M14. The other ammo related issue is primer sensitivity. Never single feed a round in the chamber and drop the bolt. Always feed ammo from the magazine.
There are commercial loads that it is not considered safe to fire through an M-14 type rifle. The very heavy loads (175 to180 grain and anything considered "light magnum") can cause excessive pressure...
So you are saying we should not shoot 175 gr match ammo out of our M1A?