[Hilton Yam]

I was perusing the Brownell's catalog for the millionth time, and of course found another tool I didn't yet have -- a chamber reamer. Clymer's are $68 and Manson's are $48. Is the Clymer unit $20 better?

All the reamers have integral throats and it would seem that the chamber diameter is pretty much fixed. Do I understand correctly then that turning the reamer cuts a fixed throat and changes the depth of the chamber all at once? It would seem that in trying to clean up the chamber diameter, that one could end up having excessive headspace too. Input from the forum?

 

[Peter Zahn]

Clymers are all I used and they have not let me down.

Chamber diameter is fixed to a certain point only. The back of the chamber as you go deeper gets bigger in diameter since it's a tapered reamer. If you go too deep you indeed can ruin the barrel by having too much headspace. That's why you should know what your headspace is to start with. A go-guage and feeler guages work great.

One thing, the .45 has a pretty generous headspace tolerance. Don't use all of it. That can creat more problems depending on what else has been done to the chamber ramp, i.e., too deep a ramp. You might expose too much of the case.

 

[10mm]

Are there certain brands of barrels that use a particular brand of reamer to cut their chambers? I ask because I would like to re-chamber a S&W 940 to 9x23, but don't want any ringing in the chamber. I re-chambered a HK .40S&W to 10mm and it had a ring in it. It is off getting re-cut by a friend with a custom reamer. I want to avoid that next time around. Apparently HK makes the chamber a hair larger -- I guess for more reliable feeding/chambering.