After brazing of the barrels the breech end needs to be machined for the hidden third fastener projection and for the correct breech angle to mate against the breech of the action. The protractor shown in the second photos is used to set the exact angle. It should be noted that the cartridge chambers were rough reamed prior to the profiling of the barrels in order to ream them to exact center of the bore. The barrels were hung to the far left side of the vertical mill and head of the mill rotated to the left over the barrels. And as you see the barrels are held in a small precision vise and that vise is held in the large 6 inch mill vise.