ACOG eye relief vs. conventional scopes

[Z-Michigan]

I recently bought an ACOG compact 1.5x16 model, and I have a variety of conventional scopes in the low to middle quality level. I have noticed a big difference in how the ACOG works compared to the conventional riflescopes, and I want to know why.

With a conventional riflescope, any model I've tried, the eye relief is a very narrow band - your eye must be at least 3 or 4" away from the eyepiece, and not much farther - the band is only 1/4 to 1/2" or so. Too close and the image shrinks to nothing rapidly and gets blurry. Too far and you're mostly looking at black space with a funny little image in the center, with blurry edges. This has been normal in my experience.

With the ACOG, I am surprised to find that there is a much wider sweet spot of eye relief - I can move my eye within probably a 1.5" to 2" range and have basically the same sight picture. In addition, if my eye is too close I still have a perfectly good image that has not shrunk or become distorted. With my eye almost touching the lens I can see a square pattern of edges, which I believe is the edges of the prism inside the ACOG. If my eye is too far I do get the black circle around the edge of the image, but it doesn't get nearly as big, nearly as quickly as with a conventional scope.

I realize that 1.5x is very little magnification, but I have compared the ACOG back to back with a 2x shotgun scope and the 2x shotgun scope behaves just like every other rifle scope I've used, in stark contrast to the ACOG.

So, can anyone tell me what design feature makes the ACOG so much friendlier in eye relief? And are there any other scopes besides ACOG models that have this same friendly, wide range of eye relief with a good sight image?

 

[Z-Michigan]

Anyone - Bueller - anyone?

 

[kestak]

Greetings,

It is very simple: ACOG is a combat sight system. Trijicon litterally put millions of $$ in R&D and they found out what is the best sight system for our Heroes.

My wife has an ACOG on her AR and I am seriously looking to replace my Eothech with magnifier system for an ACOG too. I shoot way better and faster with the ACOG. (And she shoots way better than me too with her ACOG).

Thank you

 

[Dr. Tad Hussein Winslow]

I don't know the exact design feature, but I talked to a Trijicon rep once, and there are MANY inter-related intracies and tradeoffs between focal length, # and type of lenses, overall scope weight and size, magnification levels achieved, and eye relief, both length and range. They cannot always "do it all" even with the millions into R&D, due to some tradeoffs that just cannot budge - which is why for example, the 30mm 1-4x24 Accupoint has horrid eye relief, at least *relative to* the 1.25-4x24 1" Accupoint. See - just eliminating 0.25x of magnification on the low end (going from 1.25 to a true 1.0), and going to a 5mm wider tube changed all the intricate balances of the various specs on the scope, so that getting really good eye relief like the forerunner (the 1.25-4) was impossible.

I will say that (a) Trijicon products are indeed generally amazing and well worth the money, and I plan to get many more (and the clarity & usually-generous eye relief are one of the main selling points, but not the only ones), and (b) whatever feature or combination of features Trijicon DID figure out and use to get this eye relief range, Nikon also figured it out and greatly improved it! The Omega/Slugmaster 1.65-5x36mm scope, when set on 1.65x, has FULL edge-to-edge view all the way from 5.5" out to around 13.5" and everywhere in between - amazing.

 

[Z-Michigan]

Thanks for the replies. Can't say much has been cleared up though. I find the flexible eye relief extremely useful on a rifle that may be used quickly and/or in awkward positions, and am still wondering what other scopes have such flexible eye relief. Sounds like that Nikon Omega is one option to look at. It does seem that while the compact ACOG is available at $550 (certain models, at SWFA) that it's a killer deal.

 

[Zak Smith]

I haven't used the 1.5x ACOG but one aspect of the TA11 that makes it similarly versatile is the size of the exit pupil.