This is not a chamber issue and has nothing to do with the barrel.
It's your firing pin assembly based on what you last said.
Do you encounter the issue just cycling the action without any ammo?
If so then it's the firing pin assembly. Something is catching or creating resistance within the receiver and causing the bind.
I fixed weapons in the army for a living and if there is one thing I took away is that if you start taking away parts and then somehow the issue is fixed then you focus on that part.
Also when it comes to firearms it's almost always something simple and overlooked. I wish you posted pictures so we can get as good a look without hands on.
Hope you fix it!