I just bought a new gen 4 model 21 and have not made it to the range yet but will this weekend. I have 1911 45's but never a Glock until now. I have the 26 and 19 and love both. For target shooting in 1911 45's, I use 200 grain lead wadcutters, but i know you cant use lead in glock barrels. I may consider an aftermarket barrel to shoot lead at some point, but which barrel is best? I would want a drop in fit with no gunsmithing. Or am i better off to just stick with FMJ bullets for practice and stay with the factory barrel? Thanks for any advice.