Last year I couldn't get my cheap traditions 50 cal. black powder to group at 100 yards. I was told it was a problem with the scope, so I changed it.

I sighted the scope at the range the other day. It was grouping well, but when I got to the 100 yrd range, it would shoot one or two well then throw a flier about 6 inches off.

Is this due to the barrel needing to be cleaned after about 10 shots or is there something else wrong.

I shoot 100 grains of the pyrodex pellets and I believe the 240 gn. XTP by Hornady.