I am having the hardest time getting rid of my unburnt powder problem in my 45 70. It is a Marlin 1895 SBL with the short (18"?) Barrel. I am loading 300 grain Hornady Hp bullets with IMR 3031 powder. Even at 54 grains powder (1725 fps) I can dump a little bit of powder out of the casing after I shoot. I am crimping my loads as well. I am using CCI 200 primers. Am thinking I might need to try the CCI 250 instead. Also thinking I may have to try a faster powder due to the short barrel. Was thinking Reloader 7 but it looks like it may not be that much faster than the IMR 3031. Any ideas?

......the occasional hunter wielding a hopelessly inaccurate rifle, living by the fantastical rule that this cartridge can deliver the goods, regardless of shot placement or rifle accuracy. The correct term for this is minute of ego.