This is a follow up to an earlier post. My M1A is stretching brass like crazy and I wanted to know why. Now I am really stumped:
My M1A's bolt won't quite close on a 1.638" headspace gauge (Forster .308 Win field gauge). The gauge goes easily into the chamber.
I used my RCBS Precision Mic (.308 Win) to measure both the headspace gauge and the brass that I fired in the rifle, with the gas valve shut.
The fired brass measures .006" longer than the headspace gauge that the bolt won't quite close on.
Couple of details: Like new rifle probably has less than 500 rounds through it. New Black Hills Match ammo was used when shooting with the gas valve shut. The bolt was stripped, and all parts, chamber, and Precision Mic thoroughly cleaned before measuring. Headspace gauge is brand new and there are no burrs on the brass.
With the gas valve open the brass stretches an addional .003". Various loads stretch about .013" to .018" total on one firing depending on if the gas valve is open or closed.
Any ideas how my fired brass is coming out substantially longer than the chamber when I am shooting with the gas valve shut and hand cycling the action?
My M1A's bolt won't quite close on a 1.638" headspace gauge (Forster .308 Win field gauge). The gauge goes easily into the chamber.
I used my RCBS Precision Mic (.308 Win) to measure both the headspace gauge and the brass that I fired in the rifle, with the gas valve shut.
The fired brass measures .006" longer than the headspace gauge that the bolt won't quite close on.
Couple of details: Like new rifle probably has less than 500 rounds through it. New Black Hills Match ammo was used when shooting with the gas valve shut. The bolt was stripped, and all parts, chamber, and Precision Mic thoroughly cleaned before measuring. Headspace gauge is brand new and there are no burrs on the brass.
With the gas valve open the brass stretches an addional .003". Various loads stretch about .013" to .018" total on one firing depending on if the gas valve is open or closed.
Any ideas how my fired brass is coming out substantially longer than the chamber when I am shooting with the gas valve shut and hand cycling the action?