Got a chance to try out my K22 X-trim today as well.
Conditions
- K22-Xtrim cleaned and lubed, small diameter recoil spring installed
- tested in an out door range @ ~2 degrees Celsius
- ran through 5 * 10 round mags of each ammo
Results
So definitely looks like it's going to need high velocity ammo for now, at least until it breaks in. The lower velocity bulk stuff like Winchester Wildcat and American Eagle 40gr RN didn't have enough recoil to push the slide back far enough to eject the fired casing. Not really surprising, I've only had this cheap bulk stuff work well in a couple of my .22's.
Had a surprising high number of FTF's, but easy to squeeze off another strike in double action. All FTF's went off ok after the 2nd strike. Looking at the fired casings - the primer strike is not as deep as my other .22's. Also, as tracifan68 mentioned, I did notice that occasionally the slide did not fully return to battery (usually the 1st round of a mag). This may have increased the number of FTF's. Not going to bother putting in the heavier recoil spring though as most likely it won't cycle even with high velocity ammo. Will just keep my eye on this - can just push the slide into battery when I notice it.
Overall pretty happy with my K22 X-Trim. Got it for some cheap practice for my X-Calibur as it fits my existing holster and mag holders. Will break it in with a case of Minimags and retest again.