Forrest r did a good write up on 10/22 - http://castboolits.gunloads.com/showthread.php?t=166155
to Quote him
Which explains why you need to try all types of ammo to find the flavor your rifle favor's. Matching the Ammo to the chamber.10/22 bbl's are actually a pretty good bbl, they just have extremely loose, junk chambers. Take a stock ruger bbl & touch up the crown, cut 1/4" off the bbl shank & recut the chamber with a good target reamer & you'll end up with a real sleeper. Finish reamers can be bought from $30 to $50 & their worth every penny.
A reamer chart for ptg reamers, I like & use their lilja reamer. You will notice that the smaller/tighter chambers are all match chambers.
I chose the lilja reamer because I usually shoot low to mid-grade match ammo in my 10/22. The lower the grade of match ammo the longer it is. They have found that a 22 bullet likes to be seated aa certain depth into the leade of the chamber (the distance between part b & d on the chart) for optumium accuracy. When you get into plinking/blammo/hunting ammo the bullets are way longer (as much as .060" longer) than match ammo to try to extend out further into the sporter chambers in most hunting/sporter rifles.