I've run a ton of the 200gr Underwood load in both 10mm Glocks and 40 cal Glocks, with factory barrels and with a KKM on the 40 cal. They all ran perfectly. I guess the chambers are tight bc I've never gotten bulged cases. This might also be because the Underwood doesn't seem to be as hot as the Buffalo Bore loads.
I also had problems with the 220 gr loads functioning consistently.
After messing around with various aftermarket recoil spring setups, I went back to the stock spring in my G20. It seems to work under a wider variety of conditions and bullet weights. It runs the Underwood 200gr and various 180gr bullets very well.
