I just got a brand new custom built .308 ar10 barrel. I have thousands of LC 7.62 brass that I fully prepped to shoot in this rifle. It is once fired machine gun ammo. I came to realize the brass is getting stuck in the chamber when trying to extract by hand down around the web. This brass has already been sized in an RCBS small base sizing die and the shoulder has been bumped back .005". Still stick when trying to pull out by hand and caused many rounds to not fully go into battery and even ripped a rim off when fired and left the brass in the chamber. What can I do to size them back down? They are measuring right around .470" sized at the web. I'll have to call the smith to see what the reamer dimensions were. Thanks