I didn't read the whole thread.
Yes bore finish can effect copper fouling.
Also the throat. If the reamer left a rough throat that can cause the barrel to strip extra copper from the bullets jacket and lead to a fouling situation.
The load you are running? Pressure and heat can cause fouling also as well as velocity. Anytime you start going over 3200fps....it's going to be harder on the bullet.
Type of bullet? Or should I say even from the same maker...lot to lot can vary how the barrel will foul also.
If you are still using the same bullet/load...try a different brand of bullet/or different lot and see what happens.
Later, Frank
Bartlein Barrels
