I have a stainless .50cal. Omega and find loose Pyrodex or 777 seems to shoot Powerbelt bullets just fine. You did not say what you are using the rifle for. I hunt Elk so I stay with the 300gr. to 348gr. bullets. With 80gr. 777 and a 348gr. Powerbelt 2 inch at 100 yards is pretty normal. I think slightly better with Pyrodex but I may have rushed the 777 test. I just converted it to the .25ACP breechplug and the fouling is much less and it is easier to load the .25 than the shotgun primer. The conversion is a little expensive so I only mention it as I am happy with the change. I rarely shoot anything over a 100gr. load of propellant and the Elk fall down anyway. Magnum loads are OK I guess but not necessary for me as I try to keep my shots under 100yards so I can't tell you what extended range shooting is like. If you want to talk at length you may email me at [email protected]