I don't doubt that everyone has better accuracy than I got. The groove diameter was a bit less than .454 and the chamber was a little over sized. The cast bullets were all in the 250/255gr. range and sized to .454. I tried Pyrodex, Titegroup, hp-38, 2400 and a few others. Most of my shooting was from a bench at 50 yrs.
The little I know about cowboy shooting I believe even with its dismal accuracy someone could compete successfully with the rifle. Anyway it sucked and forever frustrating. Happy others are experiencing better accuracy.