Since no one posted I'll give my .02$...
I've had the clamp on style on a .308 rifle before from Ruger I didn't care for them because it came loose after repeated firing.
I like a screwed in mount better just because if I have to I can apply some BLUE loctite to it so it is more secure and will fasten better.
Depending on your preference, you need a HIGH eye-relief scope or a specific pistol scope.
Anything from a reputable company will do... Bushnell, Leupold, Nikon, or the like. There are many scope options out there it's better to go to the store and get a feel for them. Don't overlook Red-Dot or holosights either. They are quick target aquisition models and offer eye openings of around 30-40mm +
With scopes it's pretty much you get what you pay for, if you want a dead accurate scope then you'll pay for it. With pistol it's not too much of a concern and you might get by with a Walmart Tasco for $39 I think they have them for as long as you don't plan on taking REAL far shots.
Hopefully that will help you out.
