It seems the Polymer renderer introduced a huge regression (or a bad new feature.)
When firing, impacts are well below the crosshair (try pistol or shotgun against a wall.)
If I unchecked the polymer checkbox, firing is Ok.
Did anyone else notice the problem ?
The polymer is a beta release, not a final. Your problem has been explained at the site where the developers hang out: Polymer build publicly released
I believe the problem is that is that full screen or wide screen rendering hasn't been implemented yet. If you played the game windowed, the crosshair will be correct in its aim.
If you find bugs, report them at: Polymer public builds errors/issues