Your bolt is rubbing a little on the hammer. This is normal. If you take your trigger assembly and push down on the hammer (the arched piece with a groove on the top), it should spring up & down a little more than 1/8 of an inch. Even with the trigger assembly in place, you should be able to move your bolt back and forth with your fingertips when the op rod spring is out.
When you imagine 50,000 psi driving the op rod back, the slight rubbing of the bolt on the hammer is insignificant.

Tom