Would be interested in comments on actual usage of the TA11 vs TA31.  Would be used on a M16 for shooting multiple targets (steel targets down to small wood blocks) from 20 yards to 300+ yards (already have the Aimpoint, however, can not really swap sights in middle of the run ;-).

Have read the various postings and tech specs, however, besides getting both to try (only have TA01 in the local area or at shows over the last year), best I can go by is comments and experences of others.

www.trijicon.com/


TA11 vs TA31 Tech Specs
Mag: 3.5X vs 4X
Eye Relief: 2.4" vs 1.5"
Exit Pupil: 10mm vs 8mm
Field of View: 5.5 deg vs 7 deg
Field of View 28.9 vs 36.8 feet at 100 yards
Length: 8 in vs 5.8 in
Weight: 14 oz vs 9.9 oz

In summary looks like the TA11 (donut) would be the fastest and the TA31F the most accurate (with a possible advantage going to the TA01 series at longer ranges or even a Leaupold 3.5 x 10).

It all depends on your sensitivity to eye relief.  I find the TA11 more natural and causes me less eye strain.  I dont feel comfortable at the ragged rear edage of a scopes field of view.  I feel like I am crunched way into the scope using a TA31/TA01 series scope.  

Also because the scope is further away from my eye and the field of view is smaller the TA11's magnified field of view which covers the unmagnified field of view is literally half the size of the TA31 while in use.  This allows me to have a greater situational awareness than with using the TA31/TA01 scopes.  I am less likely to get "lost" in the scope and not be aware of my surroundings.  Also the larger exit pupil of the TA11 has NOTHING to due with low light viewing because the TA31 is alreadyas large as you need it to be.  However it allows you to have your head slightly more left/right/up/down before you begin to lose the sight picture.  This is of course just an extra mm in any direction but to me its noticable.  To me 1/8 of an inch of difference in optics height is a huge difference.  You may not notice small things as much as I do.

The smaller circular area covered by the TA11, its larger tolerance for non perfect head positioning and the fact it has .308 calibrations which match up with 75 and 77 grain ammo where as the TA31 does not make it my personal favorite.

I REALLY wanted the TA31 because it was lighter, cheaper, smaller, looked better and had more magnification.  But in the end what worked better in the ergonomics department FOR ME.  Turned me to the product that was better in use instead of on paper.

If you dont have the "need" to get into the scopes "Sweet spot" and can sit back at the scopes maximum eye relief the TA31 may be perfect for you.  For the reasons I wanted it over the TA11.

Also because the TA11 has greater eye relief you can shoot more easily from improvised positions you might find yourself in such as on your back, etc.

Appreicated the ideas and things to look for.  

Had orginally though of picking one of the ACOGs and jumping blind, however, the more I learn about the differences (plus already have the Aimpoint and Leapould scopes to get by with), thinking too many options to make a good choice with out trying one first (if only the difference in eye relief / scope height & different target shapes).

Appreciate everyone's inputs on items that effects their usage.  Had missed the option of going with .308 calibration to match 75+ grain .223 loadings.

Thanks
John

i started out with a TA11 on my 20" A2. at first it was great, the extra eye relief does make for a more comfortable shooting experience. did not really care for the donut of death at ranges over 150 yards though.

then i bougth a TA31F, chevron reticle. great for longer range as the chevron is a little more precise than the donut, for me. the one thing i like about the shorter eye relief is in CQB type shooting and ranges under 50 yards. if i pull my eye back away from the scope i find that target acquisition is faster than the TA11. all i get is the glowing red reticle and no magnification. you do have to stay on the center of the scope more though.

really though, it's hard to tell what you are going to like until you try them. everyone see things differently and while we can give you our opinions they are just that. next time your at a gun show find dealer of acog's and try them out.