New Manufacture No4 Barrels

[Brian Dick]

Since I've never used one, I'd let Peter or someone else with experience answer just exactly what the test bolt does and how it works. Most receivers I've seen that are known ZF have worn bolt ways which usually means the sear is dragging or even catching on the LH locking lug. It's a given that the hardening in the sear lug recesses is most likely very tired when the weapon has seen such extensive use. I've seen two No.4T rifles that were both marked ZF because of worn bolt ways. The interesting part is that both rifles had been through complete FTR in the mid 1950's then must have failed the test gauge so were culled and surplused to the civilian market. They looked as new. One wonders why they weren't gauged and culled at the beginning of the FTR process instead of afterwards.