question about the 1.5X ACOGs

[masakari]

So i saw this picture online:
http://www.policemag.com/_Images/art...nal-1104-2.jpg
And it got me thinking... what is the maximum distance your eye can be away from the 1.5X ACOGs? Would the above config work?
i ask because i have an M1A with an ultimak rail and would LOVE to have an ACOG mounted forwards like that.

[rob_s]

That seems too far to me.

Eye relief on magnified optics isn't a matter of minimum or maximum only. It's typically given as a fixed number (although on variables you'll sometimes get a range, which cracks me up, am I supposed to move my head around as I adjust the magnification?).

That optic would appear to be the TA26S-10 which has a listed eye relief of 2.4 inches. I can tell you that I have a TA33R-8 which has a listed eye relief of 1.9 inches and I do find that number to be lower than where I actually place my head, but I can't see the TA26 number being off by enough to make the mounting shown in the picture possible.

Unless you have some physical limitation that makes the ACOG preferable, I'd just put an Aimpoint H-1/T-1 in that location and be done with it. Especially one of the new 2 MOA versions.

[masakari]

That seems too far to me.

Eye relief on magnified optics isn't a matter of minimum or maximum only. It's typically given as a fixed number (although on variables you'll sometimes get a range, which cracks me up, am I supposed to move my head around as I adjust the magnification?).

That optic would appear to be the TA26S-10 which has a listed eye relief of 2.4 inches. I can tell you that I have a TA33R-8 which has a listed eye relief of 1.9 inches and I do find that number to be lower than where I actually place my head, but I can't see the TA26 number being off by enough to make the mounting shown in the picture possible.

Unless you have some physical limitation that makes the ACOG preferable, I'd just put an Aimpoint H-1/T-1 in that location and be done with it. Especially one of the new 2 MOA versions.

I do understand all of that, and I too have a TA-33 on my M4 and my head is placed quite far from it, so that and this picture is what had me thinking. Would anybody be able to try it out just to see the distance they could get away with with any of the 1.5X ACOGs?
im not fond of aimpoints, or other electronic optics, so my plan has been to wait for a Trijicon Scout scope (which as per Trijicon representatives is in the works) but this wait is getting frustrating, and my Burris 2-7X pistol scope is bulky, heavy, and on its third trip back to the factory for repair.

[SomeOtherGuy]

I owned and briefly used a TA26R4, a version of the 1.5x16 ACOG. It was listed as 2.4" eye relief, but my experience was that eye position was very flexible and you still had a decent sight picture out to 5" or more from the ocular. However, it appears that the ACOG in the photo you posted would be more than 5" from the eye in any reasonable shooting position.

However, Trijicon also made a 1.5x24 ACOG (if I remember correctly) that was listed as having 3.6" eye relief (again, IIRC) and presumably was even more flexible on eye relief than what I had experience with. If the pictured ACOG is that model, it's possible that the sight picture would be useable, though definitely at the far end of the useable range.

[Doc Safari]

I had a TA44SG10 that had way less eye relief than I wanted. In fact, I got rid of it before ever firing a single round through the rifle with it mounted.

It needed to be mounted all the way back on the receiver where a rear BUIS normally goes, or you would have had to look through it nose-to-charging handle.

I believe quoted eye relief distances for this optic are overly optimistic.

[Dienekes]

Don't believe that would work. The eye relief on my TA47 1.5X is long, but not THAT long.

FWIW I have a TA33 3X on an M1A in a Smith mount, and the rear of the optic is about at the rear of the receiver. Not nearly as much eye relief as the TA47. I must confess I don't use it all that much (fully loaded it porks out at slightly over 13 pounds, and I'm not getting any younger!).

[TOMTOM]

It just might work, actually. I have a TA45, and the listed eye relief is 3.6", but I can still see the reticle perfectly at like 12" (or more)

I'll measure it when I get home.

It's like having a 1.5 magnification aim point. The eye relief is easily usable to atleast 8"

[TOMTOM]

Finally got a chance to take some pictures...just ignore my condo... Pictures were taken facing my patio, the distance from the front of the ACOG to the sliding door is 15 feet.

All Pictures are taken with no zoom (all i did was move the camera back), from the following distances (in order):

picture #1: 3.6" (listed eye relief)
Picture #2: 6"
Picture #3: 9"
Picture #4: 12"
Picture #5: 15"
Picture #6: 18"

Hopefully these help.

[masakari]

Wow! Im thoroughly impressed. Ok i might have found my next scout scope. Ill have to try and mount one up in person first though, of course to check eye relief and stock weld on my SOCOM16. Thank you very very much for the info and pics.
I would still like this same info for the TA47 and TA26, especially because the TA26 can be mounted extra low and therefore close to the bore.

[Amicus]

OK, I'll try my $0.02.

I'm a big fan of ACOGs. I usually have mounted at least a TA44, TA45, TA50 (not recommended unless nothing else will do), and several TA11s. Some thoughts, and I will contradict some of what others have said, but I'm just trying to be honest.

Unlike most manufacturers, Trijicon's eye relief specs are short. In my experience, you can add about 1" to their listed ER and still have very good reticule use.

I agree what Tomtom states about the TA45s, but I do not believe the photos accurately depict my experience with the TA45 at various distances. I can hold my head about 6" from the ocular with a good sight picture, but after that it begins to degrade to the point that only the center of the reticule is usable (i.e., you begin to lose the edges of the FOV).

Although I once had a TA33 (red chevron), I ditched it in a swap with a Texas deputy for a TA45 (triangle). He needed the distance, I wanted the versatility to mount the scope on a carry handle with a fixed stock. (TA33s will not mount on carry handles and permit use of iron sights; their objective bells will block the irons.) I have no experience with the horseshoe reticule, but the < 19" FoV at 100 yards really gets me concerned about what is going on outside that narrow area. Yeah, I know we are all shooting with both eyes open and assiduously using the Binden Aiming Concept , but who has not closed one eye for the 100 + yard shot?

I also believe the amber color is the way to go. The red blooms a bit too much for consistent use in bright sunlight, and the green gets lost sometimes in the well-watered New England woods where I spend a lot of time.

I am also old school enough to respect the cross hair. I can get a get a good precision aiming spot for accuracy past 300 yards, experience will tell me what the holdover is, and, at least with the crappy ER TA50, I know that the "empty spot" between the black bars represents 3" at 7 yards; good enough for closer work.

I am seriously considering getting a TA47-4 for my next build.

That is all. No offense to anyone intended.