Here is the deal.
We have lots of CQB optics, of various stripes and configurations. Mostly EOTech 551s, which everyone likes and does pretty well with. Almost all of those were bought by my employer.
We also have access to military surplus channels, through a nice government program that gives your local LE folks stuff that the military stupidly throws away or sends to the grinder (I know it is a shame, but we'd be stupid not to get the free stuff).
So our standard is the EOTech. I have also acquired a bunch of M68 Close Combat Optics (Aimpoints) free from the military. All look well used. Some don't work, and Aimpoint was unable to fix them. Some work great. For that matter, I even have an almost new Trijicon Reflex that was free from Uncle Sam, as well as some early-model Holo sights (Bushnell variety), and a handful of decade-old ACOGs. We really do have a "well-rounded" optical complement, if I do say so myself.
Most of the Aimpoints are mounted on sims uppers or on the older M16s that go to new guys, perimeter folks, and other people who don't quite rate the super high-speed gear. Some of our folks seem to have a bit of trouble working their EOTechs, though, and I just had one crater at the range, so some of our "higher-speed" folks will be working with Aimpoints for the forseeable future.
The Aimpoints are in many different configurations. All have the military mount for mounting on a cantilever mount (wwhich we have plenty of, again free) or mounting on the flat top rifles. My questions are:
For mounting on a cantilever mount, do you use the spacer or not? (I have plenty of spacers).
For mounting on the flat top, do I use a spacer or not?
Why are the dots on some of the Aimpoints dull, and the dots on others so danged bright? Is there any way to upgrade the older ones so that the dot is brighter (dot contrast as compared to the EOTech is my biggest operator complaint)?
Are ther any 1913 rails for these that can go on Remigton 870s? I have such a surplus of Aimpoints (not a bad thing) that it seems like it wouldn't be a bad idea to move some further down the chain to the Patrol grunts (or possibly on my shotguns when I go back to the streets soon; being the Armorer does have some benefits).
Any Aimpoint expert advice would be welcome.