View Full Version : Annealing 6mmbr brass.

12-24-2007, 08:52 AM
I am having some problems with my casings being a bit tight when I close the bolt on my 6mmbr. I have bumped the casings but it seems like the brass may be springing back. Someone told me to "anneal" the brass. What do I do to perform this operation.Thanks

Charles E
12-24-2007, 09:27 AM
You need to be real careful about paying attention to "someone." Now while that warning should include me & all the internet people, let's start with the basics.

It seems like you are not full-length sizing your cases. How do you know that the case isn't too big at the web or too big (diameter) at the shoulder, rather than too long at the shoulder? And while brass may spring back a little more when hardened by multiple firings, I seriously doubt that annealing the shoulder & then bumping it will solve your problem. You could test that by bumping the shoulder a bit more right now -- like .002. Differences in springback between virgin brass & many-times fires brass aren't that much.

So the first thing I would try is full-length resizing.

If you insist, annealing isn't that hard, search the archives, but better yet, get a good book that covers the proper technique. Howells DESIGNING AND FORMING CUSTOM CARTRIDGES is a good source. There is also a lot of bad advise on annealing out there (more "someone"); done wrong it ruins brass, and done really wrong, can be dangerous.

12-24-2007, 09:53 AM
+1 Charles.

I was having a similar problem until I switched over to a small base die for my 6BR. The problem was at the web of my cases, the body die I was using wasnít sizing this area down enough. I made a case gauge from the barrel cutoff just to measure the shoulder and the bump. I believe Stony Point also makes a tool to use with your calipers for this. I would just screw my FL die down or in about an 1/8 of a turn at a time, sizing the brass and checking for fit each time before I annealed anything. Stop when the bolt closes smoothly. If you donít have a FL die, buy the Redding Small Base Bushing Die and appropriate bushing for your loaded rounds, life will be easier.

Charles E
12-24-2007, 10:41 AM
. . . If you don’t have a FL die, buy the Redding Small Base Bushing Die and appropriate bushing for your loaded rounds, life will be easier. Before you buy a small base die, see if you can get a copy of the reamer print of the reamer used to cut the chamber. If it is a factory chamber -- I imagine it would be a "small" factory, such as Cooper, they too can help you out.

The point is that the die should match the chamber. For the base, a FL die about .003 smaller than the chamber is about right; I'd go with that at the shoulder (diameter) too, others will argue +/- .001 here.

But as I read it, at this point, H54D doesn't know his chamber size, so a small base may be too small at the web.

12-24-2007, 12:18 PM

If you are "bumping" your cases using an FL die partially backed out, then in reality you haven't done anything to the shoulder anyways. The only way you can "bump" the shoulder of your case in with a specially made shoulder bump die or a FL die turned all the way down to full-length size the case.

I am one of the few proponents of proper case annealing on this forum and it is my experience that annealing brass with make it more "springy" not less, because it restores the original elasticity of the brass to anneal it.

Most of what you read on this and any other forum you should take into consideration and do lots of searching and reading to confirm or debunk the info. That includes posts by this writer, too!

12-24-2007, 01:33 PM
Regardless of the solution for your current problem, if you're still interested in the annealing process, 6mmBR.com has an excellent article entitled "The Art and Science of Annealing" at this specific site: http://www.6mmbr.com/annealing.html. It might come in handy some day. Merry Christmas !!

jackie schmidt
12-24-2007, 01:41 PM
Pay attention to what these shooters have told you. I would bet a good agg that your problem is a die problem, not a case problem.
What you are experiencing is really pretty common with many of these chamberings that are, in reality, semi-custom........jackie

Dick Grosbier
12-24-2007, 08:54 PM
I doubt it is an annealing situation, it's a not being sized enough situation.

How many times have these cases been fired ?