FlyFAmerica said:
I'm taking the concensus is that most everyone expects to have a different point of impact from a clean barrel than from subsequent shots. Is it as radical as my experience- say 6 inches at 50 yds.?
You are taking it correctly. Typically the POI is significantly different from a "clean barrel" VS a "fouled barrel". Those definitions can vary widely, but even if your muzzleloading experience is shorter than most, you're familiar with the difference between the two...
Yes, the difference in POI can be substantial. Depending on a LOT of factors, some of that variance can be reduced, but generally it can't be eliminated or negated completely (at least noticeably anyway.)
Most muzzleloader barrels can be "seasoned" to reduce the effects of fouling, but also a good consistent loading/cleaning routine can help to alleviate the grief.
Cleaner burning propellants can make a considerable difference also--but if we limit ourselves to commonly available brands of black powder--we still have to deal with the fouling. In times long past, there was a multitude of black powder brands whose burn characteristics could vary greatly. O, to have the luxury of multiple choice!!!
Just try to get your routine "perfected"; and also remember the current condition of your barrel. Some shooters will just "aim off" accordingly to compensate for the POI difference of that "clean barrel" shot. (that is what I tend to do)
Regards, and shoot safely,
WV_Hillbilly