Clark
Member
I put the receiver on a mandrel with a tight fitting shaft that went through the bolt bore of the receiver. With that mandrel in the lathe, I trued the face of the receiver. Then with another fixture I made, I trued the inner stop ring, or "C" ring to the receiver face. Now the distance from the inner stop ring to the receiver face is not .625", but some random distance.
I put a depth micrometer in the receiver and measured the distance between the inner and outer rings. Then with the barrel in the lathe, I cut the shoulder so the distance to the barrel face was the same as the distance I measured in the receiver. Then when I torque the barrel on, with grease on the faces and threads, I get both the shoulder and face to bear a heavy force and thus make the barrel to receiver interface stiffer and more accurate.
I put a depth micrometer in the receiver and measured the distance between the inner and outer rings. Then with the barrel in the lathe, I cut the shoulder so the distance to the barrel face was the same as the distance I measured in the receiver. Then when I torque the barrel on, with grease on the faces and threads, I get both the shoulder and face to bear a heavy force and thus make the barrel to receiver interface stiffer and more accurate.