I've been using a KKM, on and off, in my G20 for several years. You will see a bit better accuracy but you will be fine with either barrel. I have been reloading the 10mm at its upper limits for years and using them in the stock barrel with no problems. I have had a couple of FTF in the past in the KKM but they were rare and only when I was using a heavier spring with medium loads. The Glock factory barrel did not FTF under the same condition. That problem is my fault and no fault of KKM.