I have a couple of P220 full size .45s that I use the Sig .22 conversion kit with. I recently bought a P220 Compact and wonder if (before I get it stuck or worse) it will function properly or if there are any idiosyncrasies I should know about using it on the smaller firearm. Any ideas? Will it actually fit? Any problems with it?

I'd guess "no" on the conversion kit slide for a full-size fitting a Compact...the full-size has a 4.4" barrel vs. the Compact's 3.9 barrel.

It would be like trying to fit a P226 conversion kit on a P228.