View Full Version : 308 or 7.62 Newbie Question
What is the differance between the 308 and 7.62.
Are both round's interchangable?
Looking at a couple of rifles that show one or the other in there spec's.
Thank's for any input
12-25-2008, 05:58 PM
The chamber dimensions vary a slight bit, but for the most part you can consider them the same cartridge and interchangeable. 7.62x51 is the military spec so cases are thicker and reloading data needs to take this into account. The milspec chamber is slightly longer than the commercial .308.
Are there any benifit's to get a rifle chambered for the 7.62 over the 308 or is it just personel preferance?
01-04-2009, 10:50 AM
There is an area of overlap between the two specs. It is useful to have a chamber set up for that area of overlap:
7.62 NATO versus 308 Winchester (http://www.smellysmleshooters.net/ammopressure.htm)
Collecting and Shooting the Military Surplus Rifle (2006) - Surplusrifle.com (http://www.surplusrifle.com/shooting2006/308vs762nato/index.asp)
The Gun Zone -- .30 Caliber Ammo (http://www.thegunzone.com/30cal.html)
Thank You NuJudge.
Since this post, I also have run into articles on the Pressure question.
Seem's to be for the military piece's only
I have yet to come across anything on firing a 7.62 in a 308 except this, if there both the same.
DPMS warn's on using 7.62 in a 308, Due to wear in there FAQ's
01-04-2009, 08:09 PM
The 7.62x51 chamber has a larger neck diameter with a longer and larger throat. If you fire military ammo in a new 308 Remington 700 with a tight chamber you'll find the pressure gets up there and the bolt will be hard to lift. 7.62x51 pressure is meweasured in a military chamber. Almost always commercial 308 ammo is loaded BELOW the pressure limit for safety in private owners' 100 year old rifles. The military tends to load to near it's max pressure for performance and uses modern well maintained firearms and not concerned with being sued.
A tight chamber can cause issues with military ammo due to thick necks and pressure. 308 commercial ammo can cause gas problems in some military rifles due to using slow powder and/or heavy bullets.