As a real die hard for top quality glass on all my firearms I had to step back to some brands I normally would never buy for the bigger specialty pistols because they just hold up better than the name brand scopes do. I've used the Tasco Pro Class fixed and variable power scopes on my heaviest handcannons for years without ever damaging one, and I have a bunch of them on hand. Top dog in my handcannons was a 416 Rigby Encore, it wore a TPC 6X and I shot some pretty nasty loads in it. I've shot all the JDJ's and Super Bowers for years too. Between four 375JDJ barrels alone thousands of rounds loaded hot couldn't hurt the TPC's. Problem is the TPC is long discontinued. Also had great luck on the JDJ's with the Simmons Gold Medal, but it's also a discontinued model. Of the two I prefer the TPC though, by a large margin. While I use mostly Burris on all of the tamer pistols, I personally don't like or use their posi-lock. Probably not much help, but has been my experience.
L.