Fireforming used brass

[squirrelsnpr]

I was considereing punching out my 223 Remington to a 223AI or rebarreling to 20 Tactical. I have tons of used brass from over the years of collecting. Is it ok to fireform this brass? Someone told me it was best to fireform new brass. Would there be a difference between the new and used fireformed brass?
Thanks,
Mitch

 

[CJ6]

Fired brass work hardens from firing /sizing. It's best to anneal your used brass then fireform.

 

[Adam Morris]

Mitch, I have made up 20 Tac. brass out of both new(Win.) and used brass( win., BHA, LCC WCC) and have better results annealing the used cases, but have had success by not. I tried different methods to make the brass for curiosity's sake. I shoot a .229 neck 20 Tactical that Greg Tannel put together for me, and maybe the tightish chamber helps with split necks with the cases that have not been annealed( haven't ever had one), but it does seem that the shoulder fills out a bit sharper with annealed cases. BTW, if I had to "do it all over again", I would still go with the 20 Tac over the 20 practical and 204. It is an absolute "death ray" on crows and with the application of a 32 gr. VMAX at 4250, the crow's spontaneous disassembly is soul satisfying. Not to mention the superior case design and coolness factor. Just my unbiased opinion.

PS. 4198 at the higher end may cause unanticipated pressure related issues that can best be avoided by using 322 instead.

Regards,

Adam