I have no perceived difficulties making the brass from 5.56/223. Thats the reason i was asking. I thought it may be easier to use the 7mm tcu since it was cheap and already cut down some. I have formed various brass from other parent cases. Recently it has been 35 whelen. Not that its the same as making 300 blackout as it requires nothing other than running it through dies. I was hoping that someone that has made some 300blk brass would tell me to use the 7mm tcu. I can get probably 500+ rds of it for $20. Anyway, ill let you guys know if i decide to try it. Thanks again.
