I have a M14A2, with all GI parts, in 7.61 X 51 that I want to reloading for. As a result, I purchased a set of RCBS Win. 308 small base dies and Precision Mic. A check of some fired cases reveals that my M14A2 has a very tight chamber. Fired cases measured about 1.630. The minimum ANSI/SAAMI tolerance for Win. 308 is 1.630 – 1.640.

I ran a box of brass through my small base sizing die and they came out with almost an identical measurement of 1.630. I when measured a box of Remington .308 and two box of NATO 7.62 and determined that the case lengths ran about 1.627 – 1.628. As a result, I made up a dummy round to check for ease of chambering and found that the bolt does not close easily on the reload. It does close nicely on the NATO and commercial ammo.

My questions are as follows:

1. Should I increase my rifles headspace .001 or .002 to accommodate my reloads or should I go with a die that resize the case closer to new ammo lengths? I only have about 250 – 300 rounds through it and heck, another 1000 rounds might increase my head space .001.

2. Is my RCBS die sizing my brass properly? I bought these dies thinking they would resize back to new ammo lengths. And, yes I am using an RCBS shell holder, my shell holder touches the die and the press cams over at the end the stroke.

I look forward to your thoughts.

Thanks,

Art

If the rifle fires arsenal and factory loads 100% then I would leave it be. The chamber will not get smaller as it is used.

Instead call RCBS's 800# and talk to them. They will take care of it I am sure.

Of course one could just dedicate a Lee shell holder, modified if necessary, and load away for now. Sand the top off of the shell holder till the case chambers as you want it to.

ArtD, try trimming a few thousanths off one of your cases, and try it.
Regards, Curley