I have acquired an older Leupold MK4 M3 10X scope. The turret is specific for the 308WIN cartridge, with adjustments in yards. Or so it appears. All of the hex set screws in the elevation and windage turrets are stripped. I want to order replacements and hex keys from Fastenal. They've come through for me in the past. Does anybody know what the thread size is for these set screws? What is the diameter of the screw? What is the usual hex key size? It may be .050. I will email Leupold customer service as well. I've read other forums and posters state that the service department doesn't know what the thread size is, but will send one free (?) I'd like to buy a bunch. Also has anybody tried using set screws with Torx heads? Seems like they would be less likely to strip. In other forums, responders mention black set screws for turret use, in lieu of the silver set screws, which are prone to stripping. I assume it's a different material, or is it just a coating? Thanks for any feedback.