<>I'm another fan of the mk series. I've only owned mk ii and mk iiis and they eat everything pretty reliably. Might hiccup I bit more often with Winchester 555 or similar low end fodder but like others, even golden bullets run over 95%. Maybe you got a lemon or a roughly machined one. My current mkiii 22/45 is a mag dumping machine. My buck marks are just as reliable. A few Tandemcross mods and their even more fun to shoot.
The mag bumpers and the bushings are excellent. The triggers aren't bad either. Fairly tune able for over travel and have a great predictable feel. As far as ammo I run mostly blazer 22 solids, fed automatch or golden bullets. The first 2 take the cake in reliability and accuracy for low end ammo.
Now my performance center Victory was another story. Failures to eject out of the gate. Sorted that and had a frame screw work loose. Next was the top rail for the sight. Really let down by my PC guns. 3 or 4 consecutive range trips with issues popping up. The ejection issue was well known by everyone except the people at SW that put them together! Had to bend the frame mounted ejector a mm or so.