Anyone used any of these? Thought it might be an inexpensive option for a couple lower end builds. The interesting statement I saw on their description was: "Our proprietary steel alloy ALPHA2 Scope Mounts are machined with an exactness that is both strong yet ductile that allows our rings to form around a riflescope, yet will not damage scope under proper installation." It also says the mount is Aluminum, but it mentions Steel rings, so perhaps just the top cap is steel and the body is aluminum.
That kind of sounds like what it seems my Warne X-SKEL mounts used to do, before I stopped using them. They always seemed like the top caps were formed a bit "tight" and as you tighten them they "formed" to the scope tube. Never had one slip, but they were a pain in the ass to tighten without the scope moving, and they leave a lot of marks on the tube, compared to better mounts like Badger/NF/Seekins that seem very precisely machined to the right diameter and roundness.
Probably best to just stay with the known quality of NF/Badger/Seekins/etc. but sometimes there are diamond's in the rough, not sure Sig has ever made one though