I agree 100% with Gary...amazing since most of the time he is full of crap!
I'm kidding, of course. I've used 36x with a 10" barrel. I didn't keep it on just because it stuck out past the end of the barrel and I didn't like the residue/deposits that would build up on the end of my nice scope. As a result, I bought a Tasco 6-24x and I really don't care if it "looks" nasty as long as it shoots. I do not experience any trouble at all with the fact that part of the scope is absorbing some of the muzzle blast. I'm not sure if I would want to try this with a higher intensity round though...and certainly not with one of my nice scopes to start with.
I would have to ask you again to clarify what type of shooting you are planning to do with it. If you plan to shoot IHMSA offhand events then by all means...get yourself a mid-rise or high-rise scope mount and blast away. If you want to shoot freestyle events (creedmore position or some other hybrid) then you should certainly consider a Ken Light UAS scope mount. If you are wanting a bench gun, then keep the scope as close to the bore as your objective lens will allow you. Bret