I formed my 7mm TCU brass using my standard RCBS dies. No issues or splits. The brass is once fired Dakota with the Lapua head stamp from CorBon 223 premium ammo.
i was going to load ww cast boolits with lube & gas checks for my loads through a 10" Contender.
can I use mild ~10 grain Unique loads for the initial fire forming?
Or do I need to ramp up to IMR 4064 or 4895 loads the first time?