I'm still working my way through getting ready to chamber a barrel. One of the things I've read related to chamber finish with it being writted that one shouldn't get it too smooth. The thinking was that a smooth chamber would increase bolt loading.

Then I found these two articles on the WEB:

http://www.varmintal.com/a243z.htm

http://www.varmintal.com/afric.htm

The conclusion is that until the chamber finish is smoother than it is possible to make it in any practical way, bolt loading doesn't increase much at all. Maybe 2% between a really rough chamber and a shiny one. The big difference is in the stretching of the brass which is far worse in a rough chamber than it is in a smooth one.

After reading them, my thought is to go for as smooth a chamber as I can get to minimize brass stretching.

Any thoughts?

Thanks
Fitch

After cutting the chamber I will generaly wrap a piece of 600 grit on a dowel, and with the lathe spinning at around 600 RPM will polish a half dozen passes or so staying just on the body of the chamber don't go onto the shoulder.

quote:

Originally posted by Rhys:
After cutting the chamber I will generaly wrap a piece of 600 grit on a dowel, and with the lathe spinning at around 600 RPM will polish a half dozen passes or so staying just on the body of the chamber don't go onto the shoulder.

+1

I use a brass "dowel", split to hold the polishing cloth, or XXXX wool I sometimes use and I DO polish both the chamber shoulder and the neck for my personal rifles. Does not appear to have hurt performance in any way over the last 15 years or so of having added that to my "norms".

My hornet has a rough chamber and it does damage the brass, so, I lube the loaded cartridges quite well with 'smoke stopper' (STP?) and that makes the brass last forever. I do the same with my Lee Enfield and with that too, the brass lasts forever (Except for the occasional split lip when I forget to anneal). I got this idea from a gun builder years ago, when I complained of getting only three firings before insipient head separation. (He did mention the controversy around that practice but he assured me the bolt was designed to take the full load and then some).