On my Mausers (except for the one with a McMillan's stock where I had them add a rear pillar), I glass in
this ferrule at the rear screw to provide metal-to-metal contact. This is especially true on military actions vs. commercial. I had an old riflesmith recommend this to me on a VZ24 build because of concerns that the rear of the action could bend if over-torqued; his particular concern was around trigger/sear trigonometry.
