I have Leupold 2x's on both my .50AE and .44 Desert Eagles. The .50 wore a Leupold Gilmore for awhile, but the recoil of the slide kept taking chunks of glass out of the objective lenses. It also wrecked a Simmons Gold Medal 2-7. The Leupold 2x's hang just slightly over the end of the 6" barrel depending on what type of rings you're using (I have the MRI see throughs) but if I was going to do it again I would get one of the newer barrels with the full picatinny mounts cut in already, or get extra high Burris style Tactical mounts that have more bearing surface as the Leupold has slid in the weaver see throughs (may have been due to the mounting screws loosening slightly due to recoil/slide movement, but not positive.) Also be aware that depending on the load the .50 likes to put the empty brass right back up over the top of the rear sight so if the scope is mounted too far back it could jam, or if it's too close to the rear sight it may put the brass right into the lens of the scope/red dot. I like a red dot for the .44, but with the recoil and torque from the rotary bolt/slide coming back on a DE I'm not sure any of them can stand up to a .50 forever so you may want to consider periodic replacements! I've had the same Leupold 2x on my .50 for nearly 9 years and it won't likely wear anything else until that one breaks. A 10" won't dampen the recoil on the .50 all that much nor will it extend your range tremendously so if the 6" shoots decent I wouldn't waste the money (I sold both my 10" barrels and kept the 6" ones as they are lighter and handier to pack/shoot.