I also have a Model 21 in addition to the .32ACP version. The .22LR is a little smaller, but not much. It was very unreliable until it was broken in. The instructions suggest 200 rounds. It actually took 500 high-velocity (1,300fps listed on the box) 40gr bullets to break it in. It does not like less than 40gr bullets (30 and 32gr are out) and does not care for anything other than round nose bullets (forget SWC or hollowpoint SCW). Eventually, it got broken in enough so that it could use other cartridges reliably. It is a lot more accurate than I would expect.
The 32ACP also took a lot of firing to break it in, but not as many as the .22LR. I think it was about 200 rounds. Since I reload, that is not a problem. I would shudder to think what it would cost if I had to buy all of them, especially about 3 or 4 years ago when I got it. I have had the .22LR for at least twice that long.
I have read reviews that said pretty much the same thing. Is yours the matte black version or stainless? Did you try 'polishing' any of the parts? I heard the matte black was more prone to require break-in because of the finish. You would think what you pay for a Beretta it would be a little more reliable.