Crimping the brass has had no effect, positive or negative. The gun is a TC Contender rifle, 22" bull barrel. Most of my reloading specs come from the 30-30 pistol section as I looking to use a bullet with a better BC than the standard tube mag loads. I've been through NBT 125, 150 & 165's. Sierra 135's & Barnes 130's. The 165 NBT shot the best with a 5 shot group @ 1 3/4" @ 75 yards. I have tried IMR 4895, 3031 & H335 powder. I got my hands on some W748 & R15 and have some Sierra 165 BT's loaded for the range. I load or have loaded for the 204, 222, 223, 22-250, 257, 270, 308 & 30-06 and have never had this much trouble finding an acceptable load. I know you really like the H4895 but I have money invested in all these other powders already and that doesn't include 4 or 5 shotgun powders so I'm hesitant to go buy another at this moment.