by the time I saw an ERMA carbine in the late 1960, I already had an M1 carbine, and so in my youth, no desire for a "mere" .22. in that time ammo was easy to get and cheap both one of the groceries we shopped at and the Bait and Tackle place we used had both USGI surplus ball in the 50 round boxes and French Military Berdan ( corrosive and almost half price, hot soapy water was never that expensive and I got USGI RBC for free)
By 1974 I began to look at them differently. Yes, the un-ending supply of ammo was suddenly ending. I was in Germany and a gentleman at my German shooting club showed up with one. I was concerned there may be an issue with one of the law enforcements types as Germany had recently changed their gun laws to make semi auto rifles much more tightly controlled. Turns out all was fine. If one happened to be a member of the West German version of the National Guard one could still own an HK51( to have at home for when the Russians showed up) and oddly one of the little Erma .22 M1 Carbines for "training". I shot that one several times over the next few years. Both these rifles were to be purchased privatly on the civilian market and the German Government did not issue either.
An other over age Reservist had an HK 51 and the HK .22 adaptor kit. Despite the HK trigger group this shot very well...but made the heavy HK even heavier. Also fired the .22 kit from a G3. I liked shooting the Erma M22 M1 better actually. BTW I qualified with the G3 several times and never got that excited by it other than in that it used 7.62 NATO ammo which I liked better than our 5.56 which several Germans described as either a submachine gun cartridge or "perfect for Women and children"
Years later I lived next to a lady in Florida that kept an Erma M22 M1 in a guitar case in her living room and was convinced her Dad had captured it in Germany... in WWII. Eventually I learned he had pulled his 20 years in the Army ending in the mid 1960s in FRG (Federal Republic of Germany) so maybe he told her he "brought it home from Germany" and she assumed he meant much earlier. She planed to use it as a home defense gun by brandishing it in all its frightfulness....she had no magazine or ammo to put in one if she had.
Both I have seen in shops since were missing magazines and last I looked magazines were not cheap.
-kBob