.22 CONVERSION KITS
A friend of mine had a Colt 1911A1 and an ACE conversion unit that allowed it to be shot with .22 LR ammo. His was actually a Service Model ACE kit, which used a floating chamber to simulate the recoil of the pistol with .45 ACP loads. That was a revelation to me—so much so that when I bought my first 1911 pistol I also bought a conversion unit. Complete Colt ACE pistols have also been sold for years, thus allowing one to keep his .45 ACP gun ready for use while still having a .22 version to shoot inexpensively.
For some of the most popular carry pistols today, high quality and reliable conversion units are available. For example, Ceiner offers excellent conversion units for the Browning High-Power, Glock 17 or 19, Beretta 92/M9, and 1911A1. Among others is a high quality conversion unit for Glocks from Advantage Arms. I have seen conversion units that are unreliable, but those mentioned normally work well.
Left: Advantage Arms .22 conversion unit installed on a Glock for training purposes.