I have pages of data from load development over the last seven or eight years that I've saved from loading for half a dozen 45-70s I've owned. I have NEVER gotten any 300 grain bullets to shoot as well as the bullets I've loaded for that are 400 grains and up. There is no need to suffer from excessive recoil either with any bullet in this caliber. To date I have yet to retrieve even one bullet from any of the deer I've shot with "light" Trapdoor loads in this caliber. It doesn't matter the distance or the angle, the Trapdoor loads go through deer like a hot knife through butter....and they shoot great besides. The 350 are marginally better than the 300 grain bullets, but not by a significant amount. The "lighter" bullets are too short for diameter and that doesn't allow them to stabilize as well as the heavier bullets. My best powders for this caliber, which is the least fussy caliber I've ever loaded for, are Rel 7, 4198, 2400 with cast, and 5744 with cast. Load them at 1200-1450fps and they only kill on one end....the critter's end. Good luck.