Glock 20 Won't Run


Well Known Rokslider
Oct 5, 2016
There is a saying in the competitive world: "It costs a lot to make a Glock not run"..... My 20 runs great with everything from my 40s&w limited reloads to full house 220 Underwoods. Only mod is a KKM barrel.


Well Known Rokslider
Jul 2, 2016
KKM barrels can require some fitting, their dimensions are slightly different for a tighter lock up than stock. I believe they offer a fitting service where you can send it to them. If you want to try something before sending it off, polish the feed ramp really well and try another magazine as well. I guess there is also a small chance it could be some weird combo of recoil management/lighter slide/spring, in that case order some different weight recoil springs and see if one works (18/20/22).
Mine just dropped in and had ran 100%


Junior Member
Oct 14, 2020
Sounds like you need a heavier spring. Marks hint at too much slide velocity. Magazine is probably screwing you as well. I ran hard cast in a .460rowland conversion, and busted the front edge of the magazine... (not as easily noticeable as one might think). Also, if you've run a lot of Hardcast, clean the chamber out with a good lead remover. It can be surprising how much lead fouling can accumulate where the bullet contacts the top of the chamber as it comes out of the magazine.

I run KKM barrels and have tricked out most parts on my 10mm's. My 10's run awesome. My .460 Rowland hated everything I tried on it, except the new recoil spring. I ran the same parts as my 10mm, and took 90% of it back off. I mention it because had super high slide velocity and had similar problems.

If a new spring and different mag do not work, just swap something out with a stock part until you figure out what the hold up is (as mentioned in a previous post).