[Hob Hayward]

That is bizarre. I've never heard of a bolt jamming other than from a bit of paint shell stuck between the bolt and body. Are you sure everything was put back together right? Are you using a spring kit? Are the o-rings all around the gun still in good condition, are they lubed? Have you lubed the bolt and striker well?

Especially check the striker o-ring and replace it if you haven't already.