Mike - clean the gun and cases, then clean the gun and cases, WEEKLY until you are satsified it is clean.

Perchlorate fouling, can cause deep, sharp-edged and angular pitting, not just rust in steel and iron. Successive firing, deepens these sharp edged and angular pits with each firing impluse - it is nasty stuff.

If you can possibly get real black powder, please do so.

I hate this subject.