My Gladius, like some others, would turn off if the wings were rotated just right. The problem seems to be that the only point of continuity between the body and tailcap is the indexing nub on the cap with the sides of the groove in the body. The end of the barrel does not contact the base of the tailcap and if you rotate the wings Just Right it centers the indexing nub in the groove and the only contack is lost. Here's the fix: I formed a nearly complete ring of solid copper wire 1mm thick (18ga?) just a little smaller diameter than the inner tailcap and seated it to the bottom of the cap. (just get it down past the indexing nub, and screwing the cap on will finish it.) This allows the end of the light body to contact the end of the cap and it has worked flawlessly ever since. I have tried many, many times to make it fail and can not. BTW Night-Ops is sending a new tailcap with no hassle of any kind.