Re: CQB Optic?
CQB Optic for work within 75 meters?
At the risk of overanalyzing the hell out of the issue, I'll stray a bit. Keep in mind this is my personal opinion.
The choice of any optic really depends on the rifle itself. If your working rifle has a limit of 75 meters, you are likely dealing with a short barreled (under 14") rifle that is pushing maybe 3 or more MOA at 100 yards. Aimpoint or Docter seem to shine in close quarters, where the size of the dot does not obscure the target at longer distances.
What I learned way back in my basic days in 1977 was that the maximux effective range of a M-16 with a 16" barrel was 450 meters. That is really about the maximus effective range of the military 5.56 round in those days, using iron sights. While I did score hits on the 450 meter pop up, I do recall it was a bitch, and would not want to bet my life on such a shot. For most people, 250 to 300 meters is probably more the max. My concern about the dot and hollow sights at ranges of 100 meters and beyond is their siae relative to the target at those ranges - it covers the target. That makes an accurate shot at those ranges problematic (probably better off with irons).
I just went through this drill with a new rifle. An AR with a 16" barrel in 6.8 SPC. The 6.8 offers more range than the 5.56, and the maximum effective range for the 6.8 is somewhere in the 600 meter range. It wound be nice to have an optic that could cover you up to your rifle's MER. Using the old rule of thumb of 1X for every 100 meters, a 6X scope would be a nice to have.
But what about the close shots? A fixed power 6X scope would be tough to view those close targets. Instead of a point ubscuring the target, you'd have a sight full of the target. So to get the most out of one mounted optic, you'd want a variable power scope.
1X would be ideal at the low end, but there are not a lot fo choices in 1-6 variables. There are, however, some choices in the 1.5-6 range. With just a little practice, you can still go both eyes open with the low setting.
Looking at the different options, I went with a USO SN-4, with the 34mm tube option. Tons of light, more than enough travel for both long and shorter ranges, large sight picture, and the lighted JNG reticle.
If I were going through the same drill with a 5.56 with a 16" barrel, I'd probably settle on the 1-4 power SN-4.
My personal view is that the performance of the rifle ought not be limited by the optic you choose. Even if the majority of your work is going to be within 50 meters, there WILL come a time when you will want to hit targets within your rifle's capabilities.