When I tried Lil'Gun with Hornady brass, velocities varied more than I liked. I now have some Starline Brass, and will revisit the handloads with the BFN slugs.
I think Enforcer, Accurate #9, or even Power Pistol would be interesting to try. a 355 or 370 at 1200-1300 fps is going to shoot through darn near anything.
