I have a new mould that casts 350 gn flatnose gas check .460 bullets. I tried seating at 2.55 OAL but they will not chamber in my Marlin 1895LTD. The lever will not close all the way. I was using new Starline brass, WLR primers, A2015 powder. Bullets were Hi-Tek coated 3 times,GC'dand sized to .460. In order to not seating on the start of the ogive or past that point, I switched to Hornady's brass that quite a bit shorter, mine measured 2.03". I seated to the crimp on a dummy round and it still would not chamber all the way. I gradually increased the seating depth until it was just past the crimp groove, 2.46" OAL is where it finally chambered all the way and lever closed so it would fire as normal.
Can I use the Lee Factory Crimp die instead of roll crimping? Will that effect the Hi-Tek coating making it ineffective? Should I start with midrange Trapdoor loads? I have A2015, A5744, IMR4198, H4198 and Unique powders