Thanks for the generous offer Cayugad. I may take you up on that later. I'll try a few others first. I have some homemade Crisco/olive oil/beeswax lube to try first, then plain old spit, and maybe ballistol. I'll also try some wadding under the patch as a last resort, but I doubt patch failure is the problem.

One other thing I need to address is the peep sight. It has a really large hole, something over 1/8". It's not designed for a screw-in aperture. I want to tap some threads in it and make a screw in disc with a smaller hole.