I just purchased a 22 LR conversion kit for the SIG P220.
I mounted it on my standard P220 frame. It went on very easily. The kit would not mount onto my P220 Carry. When I locked the slide back, I could not push the takedown lever up into the closed position.
SIG P220 (West German) with 22LR Conversion mounted
The 22 caliber slide looks great. The lines are straight and the fit is very good (as good as the 45 caliber slide). There is a tiny bit of play. The barrel fits inside the slide without movement.
Finish is smooth and without mill marks
Top is rounded and smooth. The rear sight is adjustable.
SIG recommends lots of lube. The kit should be cleaned and relubricated every 200 rounds.
I purchased CCI Mini-Mags, Winchester Super X and Aguila SuperExtra 40 grain ammuntion. I also have PMC Zapper and Remington Golden Bullets available. I plan upon testing at least 50 rounds of each during my next range trip.