They are great cans with a repeatable mount, I've had my Surge for a year and my Razor should be approved any day. Now I'm debating between their new Micro 30 and an Ultra 5 for a short light hunting can.
I've been using the Surge on my Tikka ctr 260 while I wait for my Ultra 9 to be approved. It always holds zero from removing and reinstalling the can out to 1000 yards.