Last edited by whinfell; 13-09-2012 at 19:59.
Had this problem with the father in laws cz, check the ejected cases for splitting down the neck, you are fortunate not to have the bullet separated and lodged in the barrel, I'm no gunsmith but I know there was a bad batch of the .17 hmr ammo, hope this helps
start with a good clean of the following.
1, strip the bolt and clean it until you can see you face in it. bolt body, firing pin chamber, firing pin spring, extractors etc.
2, then clean the rear of the chamber face.and the small recesses that the extractors go into etc.
3, strip and clean the magazine too.
add light gun oil to the areas that are safe to do so and check how it goes.im shooting loads of hmr and touch wood still no problems.