It is the CCI ammo
The CCI ammo is the colprit of this issue in .22lr. The ammo IMO is good to use but you must clean the breech and chamber quite a bit because the CCI ammo has a coating like wax on it that builds up very quickly and causes the case to get stuck. I was almost going to head to a Local Smith when I found out the cause. Use a pick from a AR cleaning kit and you will be able to actually peel the build up from around the chamber of the effected rifle.