Ive shot 790 trouble free rounds so far. I have shot 250 rounds of remington umc 115 grain. 400 rounds of winchester 115 grain fmj. 100 rounds of federal champion 115 grain fmj. 40 rounds of speer gold dot 124 grain +p. After reading all the bad stuff on the internet about the gen 4 9mms i was nervous buying it. But after owning over 5 gen 3 glocks without any problems i figured i would take the chance. Im happy i did i love it. At first the recoil spring was stiff and i felt alot of friction when hand racking it. So i did it over and over a few hundred times before shooting it. My 1st range trip i was shooting remington umc fmjs. It was ejecting weak and in consistient most of the brass was hitting me in the shoulder. I only shot 50 rounds that day. I went home and while watching tv i hand racked the slide 700 more times. The next range trip it shot alot better the brass ejected like it should to my right a few feet away. It is broke in now and shooting great. I thought i would share that with anyone that cares