I had a brief stint in BP buffalo shooting. Though against the rules a lot of guys (myself included) used 3 grains of Bullseye pistol powder right over the primer before loading the black. This gives extremely reliable ignition. Doesn't seem to have adverse effects on pressure either. I think in a shotgun shell I would try 1.5 grains, use a trickler and weigh it out. ALWAYS make sure your powder is packed tight. The 3 grains of Bullseye was used in 45/70 and I shot an 1884 trapdoor that was original. Always used Graff 3F
