I have been experimenting with poly coating bullets lately (yes, slow of the mark) and having remarkably good success with my .310 Cadet.
I bought Eastwood brand paint powder as it consistently gets good rating and have found it coats well and bakes evenly when I do my bit.
Two groups from yesterday shot at 50m/55y using two different CBE .310 pattern bullets. The round nose is the 320-120 and the pointed bullet the 323-125 both cast in 40-1 alloy.
Cheers from New Zealand