CCI Stingers casings are a few thousandths of an inch longer than a standard .22 LR Case. You may have a short chamber in your rifle that is causing the binding. I assume that you have shot other ammo through this rifle with no similiar problems? Try cleaning the rifles chamber very well as recommended by jhm. Could be that a fouling ring has began to form just forward of the cases mouth of standard ammo, that the longer stinger case adheres too. I am not familiar with this rifle but I assume that it doesn't have a Bentz or Match Chamber. A tight chamber is essential to a good shooting rimfire. If you want to use the stingers, have the rifle checked over by a Gunsmith to have the chamber measured. Otherwise, if the accuary using decent .22 LR Ammo is good. Leave it and shoot it.