Do you think .22s really gives you much practice that will relate to shooting service caliber guns? I mean, maybe. I have not shot a .22 in a long time. I do have an Olympic-style pellet gun and it is excellent for training you to hold a steady sight picture, but with a 1 to 1-1/2 pound trigger it does not relate well for trigger control.
I have a cheap pellet gun (CO2) that is a knock off of a Beretta, and it has a long, long, trigger pull and it is very, very heavy. If you can control that trigger you can control the trigger on any gun ever made. So for very cheap ammo you can conquer two aspects of accurate shooting: trigger control, and sight picture.
But this ignores recoil. And that is my issue with .22s. They make noise, but the recoil is almost non-existent.