Rotating the pin one quarter turn was the easy way, the set/retaining screw in the front of the receiver holds it in place from moving. It is not bottomed out on the shoulder now. I still had to file the head slightly because the cocking rods pivot on the pin that is driven through the hinge pin and caps.
If there was wear on the barrel hook the gun would still be off face because the hinge pin is/was to a uniform size of .334 diameter.
In cutting threads to a shoulder, an under-cut is usually made at the shoulder so that it can bottom out.
