Originally Posted by MOGC
Back in 2010 I made a post on another forum about an odd occurrence I had with Weaver rings...


. . . I can’t understand how BOTH of those snapped off like that when there was absolutely NO accidental drop, bump, ect on the rifle or scope. There isn’t a mark or mar on either the receiver of the rifle or the matte finish on the scope. I questioned dad and he said he hadn’t taken a spill while hunting. I know that is true because we always stay with dad because of his age. The gun hasn’t been messed with in any way and just sits in the safe. It is only a .308 with moderate loads and the scope is lightweight so I can’t attribute this to recoil. Is it just too weird that both cross bolts would catch a severe case of metal fatigue at the exact same time? I’m having trouble figuring this one out…"


It wasn't fatigue (I teach the subject.) Fatigue requires a varying load, for example the head bolts on a cylinder or the loads a crankshaft sees. In addition, fatigue requires MANY cylces, hundreds of thousands of cycles. Even "low cycle" fatigue is thousands of cycles, usually tens of thousands.

I suspect they were over tightened. That is not a large thread, #6- ? It really doesn't take a lot to hold the ring where it belongs, especially if you push it forward before you tighten it down. Especially the older large diameter "flat" nuts that they used to make a special "T" handled tool for could get over torqued. Even the modern nuts, with the coin slot, will accept a screwdriver much larger than usual for that thread. So it may have been way over tightened from the get go, or over tightened a bit, then relaxed by removal, then over tightened again, etc. Kind of hard to explain without getting into a bunch of engineering like stress concentration, but this can lead to a phenomenon called work hardening. Think of it like bending a paper clip back and forth a few times until it breaks. Many call this fatigue, but they are wrong. It is work hardening.

Bottom line, you don't have to crank down on those #6 threads for the ring to work fine.

Best,
Gun Doc

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