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making a reamer?

Dave W

Aluminum
Joined
Jan 10, 2007
Location
central Arkansas
I'd like to chamber a barrel in .50 Beowulf. Chambering reamers aren't available from the usual sources.

The case is 1.65" long and tapers from .525 at the neck to .535 at the base. With such a small taper, I think it would be reasonable to make a piloted reamer and do the job by hand in the bench vise. This would be attractive since I don't have a lathe with a headstock that can pass the barrel through.

Would a simple D reamer work here?
 
How much clearance should there be between the nominal cartridge size and the finished chamber? I've mostly dealt with old military bolt-action stuff, which tends to be loose, and revolvers.

Yes, I could set up the steady, but it hardly seems worth it to taper a hole .010".
 
Yes, I could set up the steady, but it hardly seems worth it to taper a hole .010".


I am not sure what you are talking about here. I was saying just chamber the barrel in the steady rest using a reamer. You can get equally good results off the steady rest as you can through the headstock if you take your time. Either way requires you to take your time, so it is no harder.
 
A simple half reamer will do the job. You will need to know just what you are doing and be careful. Two reamers will have to be made one to chamber with and one to make a reforming (neck sizing) die. What do you want to re-chamber for this cartridge?
 
There is nothing wrong with a D reamer for chambering. They have been used with success for many years for one off jobs. It would not be a bad idea to test it on a piece of scrap first and to rough bore the chamber first with a boring bar.

While the barrel cannot be passed through the headstock, the barrel can still be chucked up and the chamber end supported in the steady rest. This is also an acceptable way to do business. If the chamber is a straight taper, it is a simple matter to bore in the lathe without the need for a reamer at all.
 
As the others have said, a 1/2 reamer is a perfectly acceptable way for a one-time job. I have made and used quite a few of them when evaluating possible wildcat cartridges.

For your project you may find it faster to set up on the steady and bore the chamber.

Where you will have your biggest challenge is in the free-bore and throat. That is the most delicate part of the chamber and has to be nearly perfect if you expect any kind of accuracy. I'd suggest a seperate reamer just for that purpose.

Ray
 








 
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