223 improved fire forming issues

[Martman]

Thanks for the explanation regarding crush fit. Also I had not heard of creating a false shoulder by following the procedure you outlined. I am fortunate in finding a forum where so many people are willing to share their knowledge. I intend to purchase new brass this afternoon but am limited locally to Winchester and Hornady. I did go to the range this morning and test fired 10 rounds in which the seated bullet touched the lands. All 10 rounds formed satisfactorily without the previous case separation signs. The loads used were 2 grains below listed maximum. Before loading another batch I am going to check new different brand brass for a crush fit. With that being said, I am hesitant to fire form near max or max loads utilizing the procedure that worked well with the 10 cases, i.e. bullet touching the lands. Perhaps it will be a moot point once I test fit the new brass. Otherwise I think I'll stay with the 2 grains below max to fireform the remainder of my Lake City Brass. Thanks again for your input.