Originally Posted by HARPERC
How much of a process is this? i'm not out of brass yet but I can see it on the horizon.
Here's how I'd do it (.270 brass):
1. anneal the case necks and shoulders a little on the heavy side (they'll work harden during the reform operation)
2. run the well lubed (use Imperial wax) thru the 6mm die till you run out of room.
3. trim the cases back as much as you can, but leave plenty long
4. run the cases thru the die again, but leave them a tad long at the shoulder and an over all length of maybe 2.400".
5. this is the finished part and can make you some really nice brass, or junk. Find out exactly how long the max over all length of the chamber is (not the throat). Now finish form your brass to get the correct headspace, and trim it to where it's about .015" shorter than the actual chamber.
6. your ready to finish fire form, and trim back to the correct 2.235" over all length. I would go ahead an anneal the case necks and shoulders one last time as we've moved a lot of brass! I'd also expect to have to shave the necks as there will be plenty of brass flow up there. These cases ought to come out better than factory 6mm brass as they're built for your personal chamber.
of course this is a little more work, but still isn't hard. The two anneal processes are critical, and will make the case fire form better in my book. I had some problems with reforming .257 brass even though I've never eluded to it in the past. The cases come up a little short, but that's not so much the issue as burning a groove in the chamber neck when using some fairly hot burning powders. We spend a lot of time and money getting as perfect a chamber as we can, and then turn right around and screw it up in 400 rounds! Still the 6mm case is not a barrel burner in anyway like some other 24 bore rounds.