Hi guys - I'm hoping for some words of wisdom in regard to some problems I'm having with a brand new KKM "drop in" (that's what I did) .40 to 9mm conversion barrel. I had the opportunity today to try out the new barrel in my 4th gen Glock 22. I purchased a brand new (factory) Glock 17 mag to go along with the barrel. On the very first shot I had a FTE, then the remaining 16 rounds fired without incident. I also had several FTF's in the duration of the 50rd box of ammo. The barrel seems perfectly fine to me, as does the magazine and I have never had a single FTF, FTE or hiccup of any kind out of this firearm. I'm thinking the problem may be that the ammunition was too light to fully cycle the slide, but it's my understanding that both the Gen 4 G22 and G17 use the same spring weight, so that wouldn't make sense. Please correct me if I'm wrong. The info below is the setup I was using when I experienced the problems. (By the way, when it works :laugh: the accuracy of that KKM barrel is stellar. I was very impressed shooting 15 yards with it.) I must have had roughly a dozen FTF's/FTE's out of 50 rounds. Unfortunately I didn't have any other 9mm loads with me to try. Gen 4 Glock 22 - 450 rounds of .40 through it KKM Drop In .40-9mm conversion barrel Glock 17 magazine Federal 115gr FMJ's (the cheapest ones I could find) First shot with new barrel: ...And - Stove pipe: Failure to feed with GF shooting: Round went "primer up" in mag during FTE: Any thoughts or input will be appreciated - Thanks!