Sounds like all you need to do is change to a finer powder - thenchange nipple and caps too. Sounds like your cleaning ritual is fine - as long as you are not overloading the oiling part. After oiling, I keep my muzzle-down for a couple of day & nipple removed. I never oil the nipple and cleanout screw. I use a small tube of Birchwood-Casey Choke Tube Lube spread lightly on threads. A 2nd choice would be a regular tube of auto anti-seize like Permatex.