I've put a couple hundred rounds through the Gen4 G21 rental at my local range - I'm sure this thing has had thousands of rounds through it with minimal mx and cleaning. All reloads. The only BTF came from brass bouncing off the lane dividers. I set the plastic tote they give you to carry your rental to my right against the lane divider (roughly to the gun's 4/5 o'clock) and probably 75-85% of my brass winds up in that tote. Seems to be pretty consistent. Happy enough with it that I'll be buying one. Good luck with yours.