05-08-2021, 02:52 PM
SDW Wrote:Just saw this thread. I figure I may as well contribute my experience. I used brass shim stock for my rifles that needed a little help. Brass was the only metal my local industrial shop carried in small quantity. I would have preferred steel, but I figured metal is metal. It has to be better than slopping glue on those surfaces, which will eventually just harden in any old shape you let it conform to, whether it's a good shape or not. A metal shim on the other hand, which has consistent thickness throughout, ensures that the extension has to go into the receiver perfectly straight, and stay that way permanently. I think the 0.004" shimming material worked well for me. And this was after doing a little lapping to true the end, I should also mention.
FWIW, on my uppers I did not need to do any freezing. I just blasted my upper's forward end with a Bernz-o-matic propane torch all around for a few seconds. After that I was able to tap the barrel shim-wrapped extension into the receiver.
Brownell's has steel shim stock...
https://www.brownells.com/gunsmith-tools...od589.aspx
I refuse to be victimized by notions of virtuous behavior.