The 22 conversion units, with one possible exception, are not meant to be a subsitute for a 22 cal pistol. They are provided so that one can use an existing frame and shoot less expensive ammo in practise or to familiarize a younger shooter.
The exception is the original Marvel unit which was designed to offer bullseye shooters the same grip in shooting the 22 stage as they used for the CF and 45 stages. My Marvel unit is superbly accurate and has never malfunctioned in firing almost 10,000 rounds of quality SV ammo.