Without being entirely sure, it seems to me that US-imported P22s (from the German factory in bits and pieces) are assembled and marked w/the importer's markings in the US (there is a variety of markings/assembly lines (?)). These P22s are referred to as "US-made", as opposed to the "real" thing that came out of the German assembly line in one piece.
Theoretically the two sorts ought to be the same in specs as well as in function. But, from the little I gathered over the past year or so, they appear not to be the same. Or are they? Could some other factor(s) be involved?
The "German" ones appear to work flawlessly, while the "US-made" appear to be plagued with issues.
Some may say that US users tend to shoot Hi Vel or Hyper Vel ammo, while the Europeans use mainly Standard or Subsonic ammo in their P22. Consequently, the US owners wear the little pistol more readily than the Europeans, because the Standard/Subsonic ammo when employed in quantity is not too punishing. On the contrary, thousands of Hyper Vel stuff could be blamed for signs of excessive tear and wear experienced. But even those seem to continue to work, regardless of entropy.
Also, in Europe the P22 usually ends up in the hands of experienced shooters who know from past experience that no arm is ever shot straight out the box without a good cleaning.
From my part most of the people I know (in several European countries) who got their P22 new, they stripped it and cleaned it first, before starting to break it in (usually) with some Hi Vel ammo, before settling down to the use of Standards and Subsonics. While in the US the P22 is often purchased as a first pistol and mistakenly is taken out to the range with all the cosmoline-laden mechanism and factory lubed/greased magazines (intended to keep the arm in storage until sold), and start shooting it with Stingers and Velocitors.
Experienced American owners who have cleaned their P22, before using it, encounter fewer if any issues and normal wear, just like us in Europe.
Crete