I built a Polymer 80 Glock 19 clone and have run a few .22lr mags. through it with no problems. Follow their ammo recommendations. Once I figured out what was going on with the 9mm slide and firing pin/trigger bar to permit the gun to actually go bang, just switching to the Advantage Arms slide/mag. and it ran just fine. The guys on this web site were a great help and support in trying to diagnose the original problem when mine wouldn't go bang period. Good bunch. Going tomorrow to try out my Glockstore 43 build which I expect to be OK. If that works out as expected, I "may" try a LaserMax guide rod sight which is not suppose to work with the SS-80. Want to make sure mine is working without a hitch before ordering a $200+ laser that won't work.