I should add that I took the 350gr XTP up to 61gr 5744 shot 10 rounds with fps up to 2200 with 1 as low as 1990 primers were not only flat but deeply cratered. 1 actually showed signs of cracking micro sized and very faint signs of.gases.escaping. Some looked.fine and.I suspect the.crimp may be the.differences. its difficult to control.