13 Jan 12
More comments on rifle optics, from respected Trainers:
“You have essentially reiterated the ‘law of optics:’ (1) magnification, (2) field of view, and (3) eye relief are all inter-connected. Increasing one always reduces the other two. No way to get away from it!
I have yet to see any magnifying rifle optic, above 2.5x, that is useable with more than 10cm (4″) of eye-relief. There is no getting around the above-mentioned trade-offs. Maybe in the future, we will see an optic with a video-regurgitated image that features unlimited eye relief, combined with significant magnification. Until then, here is my opinion:
Red-dots (Aimpoint and EOTech) can use a rear-mounted magnifier that can be flipped in and out of the way, as you indicated. But, as you also indicate, the system is bulky, and one does have to take the time to move the magnifier into, and out of, place, as the situation warrants, doing his best to guess, ahead of time, which mode shall be most appropriate! In addition, for those of us with astigmatism, the magnifier will also magnify distortion of the dot. Also, these magnifiers come with a non-adjustable ocular focal-length, and thus some of us will have issues acquiring a clear image.
Hardened, fixed-power (and adjustable-power) tactical scopes (ACOG, Leupold HAMR, Elcan, et al) have the advantage of significant magnification, an easily-visible reticle, and exceptional physical durability. When batteries go dead at inconvenient times, an eminently useable etched-glass reticle always remains. However, they are all bulky, and eye-relief is never more than 8cm (3″). Corrective lenses, particularly bi-focals, are often tough to use with this short of eye relief.
Most do not have adjustable oculars, so clarity of image and reticle is dependent on the shooter’s eyes and/or eye correction. Models with adjustable oculars are recommended, but expensive.
Trijicon asserts that their reticles can be used with Bindon Aiming Concept (BAC). Simply put, some shooters can acquire the bright reticle in the shooting eye and simultaneously use it in conjunction with the image captured by the non-shooting eye. Trijicon goes on to say that two of three people are able do this. I think that estimate is extremely optimistic, as it doesn’t take stress into account, and it has the same limitations as the old Occluded Eye Gunsite (OEG) Method, in that it depends on both eyes being aligned the same. My suggestion is to exercise this theory thoroughly, with and without your glasses, before betting your life on it!
In the end, when you want magnification beyond 2.5x, you will have to learn to live with close eye-relief! When you insist on generous eye-relief, magnification will be thus limited. You can’t have it both ways within the same optic!”
*****
“I saw a sexy duel-sight setup recently. ACOGs now can be mounted with a small, zero-magnification ‘MRS’ sight on top of the ACOG. Offset is no longer an issue, but alternate cheek-weld is, and the whole thing it is awkward and bulky. Plus, the MRS sight is not nearly as rugged at the ACOG itself. I hate to think what will happen when it is dropped on concrete! However, an even greater concern is that two, separate optical sighting systems (be they offset or one on top of the other), on a single rifle, forces me to make a decision for every shot taken! When fighting for your life, such multiple choices are often more an encumbrance than a benefit. Like you, I suck at multi-tasking!”
*****
“An ‘illuminated reticle’ is not necessarily a ‘reflex’ optic. An illuminated reticle is the equivalent of shining a light on an etched-glass or wire reticle. The reticle does not ‘follow’ eye movement. ‘Reflex’ sights (Aimpoint, EOTech) use prisms to project the dot, so that the eye can pick it up in nearly any head position. That is where reflex sights get their well-deserved reputation for speed.”
*****
“Just back from the range with my suppressed AR. One quirk about running sound suppressors is that heat-mirage becomes a critical issue. A couple of magazines is workable with a zero-magnification Aimpoint, or iron sights. However, when using a magnifying scope, within a single magazine, heat-mirage makes the optic nearly impossible to use, even at 3x!
As suppressors become more prevalent here in WA, students are going to be showing up with them. They reduce 5.56 noise and muzzle blast down to that of a 22LR, but, per the foregoing, there is no free lunch!”
*****
“Chinese-made optics are trash. There may be exceptions, but I’ve never seen one!”
*****
“I often have officers show-up for training with 4x optics on patrol rifles, which are almost always removed by the time we are finished! By contrast, Aimpoint T1s routinely stay in place for the duration.”
My comment: And yet, my long-time friend and colleague, Jeff Chudwin, regularly out-shoots all of us, including accomplished Operators half his age, using an AR, equipped with an Elcan Spectre. This is the same rifle he takes with him on duty every day!
/John
