http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=320171
http://www.midwayusa.com/eproductpage.exe/showproduct?saleitemid=217984&t=22164010
Other than reticle and adjustment knobs, they seem quite equal. Both have large amounts of elevation adjustment, and the same magnification. I was just wondering exactly what the extra $300.00 buys in the Mark IV, and would the VX III be at any disadvantage over it in F-Class? Bill T.
Bill, the original Mark 4 Leupold scope was built in fixed power models (6x, 10x, 16x, and perhaps 20x), and was called 'Ultra'. Then it became the Mark 4. The 6x and 20x version were way less common than the 10x and 16x models. Etched glass reticles, a maintube wall thickness of 0.100". 100+ MOA in the 10x model, and 140 MOA of elevation in the 16x model. Typically configured with M1 target knobs (tall and heavy duty, with no screw off covers).
Leupold pulled a marketing fast one when they re-named the Vari-X III (VX-III, VX3, whatever) as the Mark 4 Variable. It was a marketing ploy. These never featured, nor do they now feature, the heavier tube thickness of the fixed power Mark 4. They feature wire reticles, not etched glass. Leupold changed the lens coating hype to "index matched lenses" instead of MultiCoat 4. Whatever. Can you see the difference? I cannot.
Add M1 target knobs and a mildot reticle, and it's still not the equivalent to the fixed power original Mark 4. In fact, it will have about 72 MOA of 'up', and its 6.5-20x50 cousin has about the same (although Leupold advertises 70 MOA of 'up' if I recall). What you need to decide is if the mildot reticle and M1 target knobs are worth $300 more. If you sent a Vari-X III, with standard turrets and a, say, duplex reticle, to Leupold for a changeout to the M1 knobs and mildot reticle, it would probably cost you about $300.
Will either of those make you shoot better? Almost certainly not. But in the world of tactical rifles, such things are considered very tacti-cool.
By the way, the fixed power Mark 4 Leupold scopes have a relatively short span -- for your rear scope ring -- behind the turret saddle. This can be a bit challenging to get optimum eye relief position, so choose your rings (not too wide, and Picatinny or Weaver style recommended) and scope base (lots of slots, and Picatinny or Weaver style of course to match) accordingly.
The fixed power Mark 4 scopes were quite a bit more expensive ($1,200 new, even several years ago) vs. the VX3 (variable Mark 4) items, but that gap seems to be shrinking. Why? Who knows!