Re: Best scope for under $1500 50mm or less
I would opt for the ST-10. I have the standard size bell but you can get the slim-line for the same price:
http://www.usoptics.com/optics/st-10-slimline.html
Even spending the extra cash for the TPAL:
http://www.usoptics.com/optics/st-10-tpal.html
From what I have seen the original Mk 4's have been of very good quality (10X). But the offshoots are the ones having problems. From what I understand from about a little over a year ago, Leupold has addressed the quality issues and is doing a much better job of it now. I know all of my older Leupold scopes have been very durable, if not even close to getting the best glass out of the deal.
The variable power issue goes back and forth a lot. In some cases a fixed ten is never enough power or always too much. I've found it's enough for what I've shot to, and that is one mile. The target isn't as big, and I can't see small detail on the target, but I can watch hits (on steel). It's good enough to keep you center mass.
On the flip side of that, you aren't going to win any contests with a fixed ten. Shooting tighter groups on a scoring type target requires you see a little better than the average bear. Any of the really top names are going to start at $2k so you might as well forget those.
That said, the scopes within your $1500 budget are:
Burris Tactical (or Black Diamond)
Bushnell Elite Tactical or Elite 6500
IOR Valdada Tactical
Meopta (4-16 Mil-dot, Meostar R1)
Nikon,
Sightron SII or SIII
SFWA SS scopes (upper end comes in just under your budget)
Vortex Viper PST
Zeiss Conquest
I've used all the above scopes and feel they will work for you. It's hard for me now to come along with all the price changes and say what is the best buy. IMO the best buy is the Meopta. My personal preference of Meopta though, is out of your range of wants, the 3-12x56 #4B reticle. All those MFR's mentioned have a variable range of power above ten, a mil or moa type reticle, and are the size you want and under $1500.
-Good luck