I am thing about it, just wondering if anyone has had any problems with it? Mainly cheek weld & eye relief issues.
The short eye relief bothers me.. 1.5"..
Does the TA31a have a second screw hole in the M16 base so that you can slide it back to the rear more in the carry handle?

Good friend of mine has a TA31 mounted to a A3 Carry handle. He does just fine. Its all going to depend on how sensative you are chaning your shooting positions. If you are flexible, you wont give a hoot, if you are sensative to change, the lack of a solid cheek weld may be bothersome to you. Trijicon lists the TA31 as having 1.5" of eye relief, but that is a conservative estimate. I'd say eye comfortable eye relief is anywhere within the parameters of 1.5" to just over 2". Here's a pic of the rifle and some of him shooting it.
[img]http://www.imagestation.com/picture/sraid60/p045f7c718e3d2a046f722c56f81cebfc/fc420f70.jpg[/img]

[img]http://www.imagestation.com/picture/sraid60/p1294767bb2efd60c62d730ba842872e2/fc42196e.jpg[/img]

[img]http://www.imagestation.com/picture/sraid60/peb3ae606fe892397c1b16294591929c2/fc422a28.jpg[/img]

Oh yeah, and there are two scre holes in the base. He is using the front hole in the picture above. I think if you used the rear hole to mount i, it would be too far ahead.

Thanks for answering my questions...that helps very much with a picture..