I saw that Teflon plumer's tape works for some small rounds?

teflon tape might work if your bullet is dripping but a pressure leak would require more serious measures.

teflon tape is mostly polyester, FWIW.

Teflon plumber's tape has been tried by many cast bullet reloaders including myself and the results have not been worth while. Run a search for this subject on the Cast Boolets forum and several pages of postings will come up.

I have been paper patching since the mid 60s and have tried just about everything you can think of. Teflon tape is NOT the way to go. Fact is 16# printer paper works better than anything at all.

Definitely consider paper patching. Full power velocities are achievable with very good accuracy. Pressure seems to be lower than with jacketed bullets with the same weight and powder charge. It also cleans the bore. More of a rifle thing.

I shoot paper patched bullets exclusively. No lead has touched my barrels. Paper patching is very rewarding and increases accuracy in every gun I have shot. Ron