In order to participate in the GunBroker Member forums, you must be logged in with your GunBroker.com account. Click the sign-in button at the top right of the forums page to get connected.
Options
.308 case pressure?
rchawk
Member Posts: 84 ✭✭
Hi gang,
Here is a question I should probably know the answer to, but I don't.
Most reloading manuals tell you to reduce loads by 10% when using military cases due to reduced volume. Now, Accurate Arms lists a 168 FMJBT load of 2230C as "37.8 up to 42.0 grains". Does this mean I should reduce the powder by 3.78 up to 4.20 grains respectivly???
Also, will a much reduced load still function a NM M1A?
As always, thanks in advance.
Hawk
I would rather be tried by 12 than carried by 6!
Here is a question I should probably know the answer to, but I don't.
Most reloading manuals tell you to reduce loads by 10% when using military cases due to reduced volume. Now, Accurate Arms lists a 168 FMJBT load of 2230C as "37.8 up to 42.0 grains". Does this mean I should reduce the powder by 3.78 up to 4.20 grains respectivly???
Also, will a much reduced load still function a NM M1A?
As always, thanks in advance.
Hawk
I would rather be tried by 12 than carried by 6!
Comments
Mobuck
Interestingly enough, I was more concerned with failure to function in my M1A at the lower end of the loading scale. I know what to look for at the overpressure end.
Won't the "auto" pressure regulation on the M1A compensate for the reduced loads to a certain extent?
Thanks again,
Hawk
I would rather be tried by 12 than carried by 6!
I think you may be confusing the .308 Winchester with the 7.62x51 NATO. While they are very similar, they are not identical. Green Lantern posted a link to a site which describes the differences in detail, and there have been several threads posted her on the subject, so do a little research. The nominal chamber dimensions for the 7.62x51NATO are a little different, and for maximum accuracy you should determine the exact dimensions of the chamber of the particular gun. One of the guys recently discovered his match tight .308 Win chamber wouldn't accept 7.62x51NATO cartridges properly as it was a couple of thousandths too small.
Having said that, the 7.62x51 NATO case does have a smaller case volume which will generate higher pressures than a .308 Win case, all other things being equal.
redcedars
http://www.smellysmleshooters.net/ammopressure.htm
Here's from fulton armory, but don't forget they are in the business of refurbishing the M1A.