The TA31F is the Chevron reticle.  This units BDC is calibrated for being mounted on a flattop receiver using the TA51 using a 20" barrel.  The TA31 (Donut of Death) is calibrated for carry handle mounting using a 20" barrel.  The TA31A is the Triangle reticle, also calibrated for carry handle mounting, but you knew that.

Some people say that the Chevron is harder to acquire in CQB situations versus the TA31 or TA31A.  Others say the TA31A obscure some of the target at longer ranges but give more pin point accuracy due the to nature of the reticle versus the TA31.  The TA31F gives pinpoint accuracy at longer range without the obstruction of the target.  On and on, won't bore you.

Six of one and a half dozen of the other.  Honestly comes down to personal preference, but most of us ARMCHAIR Commandos like to think the reticle we choose gives us the tactical advantage.  [;)]

Let the war begin!

 

When I saw your "Staff" status I thought to myself - "Shouldn't I be asking HIM this question?"

FWIW, I just picked up a TA31 and really like it!  I did A LOT of reading about the various ACOG's on the board, and have seen some postings regarding limitations with the TA31F's chevron reticle.  There seems to be a mix of those who like em', and those who don't.  Since I've never used one, I can't chime in, but if the size of the donut reticle on my TA31 is any indication, I would imagine the chevron reticle would harder to acquire when speed is involved.  It looks like a better long distance precision setup though.

Good luck with your search.

I think chevron reticule is very good for precision shooting UNDER 300 yards, rather than over that. The reticule only covers point of aim from 0 to approx 300 yards, and further than that you would have to use built in BDC for aiming.

If you are looking for a dual illuminated TA01-NSN, TA31F is the perfect ticket. Fine aiming point, much brighter reticule.

The TA31F BDC is calculated for a 14.5" (Trijicon website says 16" but I believe that is a typo) barrel firing M855 (62gr) from a flattop mount.

Things I liked about it:
Chevron gives a nice precise aiming point at 100m and 300m without obscuring target

If you are going with a flattop mount, you can tweak this BDC to a very good match for any 5.56mm and barrel combo from 55gr to 77gr.

Things I disliked about it:
Real easy for chevron to blur out or get lost if eyes weren't properly focused. Chevron seemed dimmer than donut to me.

200m aiming point is kind of vague and indefinite.

If going with carry handle mount, BDC can be tough to match and impossible on longer barrels.

Comes with TA51 mount included, so I pay extra for a mount I don't want to use (prefer the ARM #19S)

YMMV

I "kicked tires" for over a year before deciding on a TA31 for my primary carbine.  I do a lot of tactical practice, with shots from 7 to 300 yards.  The TA31 has been just what I have been needing; a combination of light weight and compact size that has improved my speed and precision at all distances in a single package.  I have it on an ARMS 19s on my flattop.

Get in touch with Mike at CSGunworks.  He will take care of you.

Bud

TA31 you had it and it's still the best choice.