Bought a Mil M4 14.5 upper and mated it to a new 6520 lower.( sorry, don't have a way to post pictures) I have looked at quite a few red dots and like the TA's. I founed this in the EE:

http://www.ar15.com/forums/topic.html?b=7&f=23&t=287691

So here is the question; Is this calibrated to a specific barrel/bullet weight ? More to the point, will this work on mine? I assumed that the calibration is related to the hash marks under the center ring. Please help the helpless!

www.ar15.com/forums/topic.html?b=3&f=18&t=229420

Good God, all that made my head hurt. How about this: I will be plinking between 25 and 100 yards with an rare foray to 200 yards. M193 ammo , carry handle mount.

Ok, Ill try again. Please tell me if that sight system will be work with my AR and is it a good deal at $740.00? I have seen these sell for the 700.00 to 900.00 range and don't want to spend that kind of money for something not compatable. I do realise that an Aimpoint for half the cost will work at short range, however, I like the magnifaction (?) and the look of the TA-31 gives me wood. Please help!

TA31F is calibrated for 62gr M855 and splits the difference between a 14.5 and 20 inch barrel. The RCO model is available calibrated for the 14.5" barrel and 62gr, or the 20" barrel and 62gr.

Thanks for your friendly, patronizing, tart retort. Once again, I’m a noob (please see member since Sept 2005 in my sig) and was not aware of the optics forum. I did take time to read the post (hence the "It made my head hurt" comment) but I did not see a 14.5 carry handle w/M193 with a TA31, only a TA31F. I looked up the Trijicon site and the specs are the same on the 31 and 31F. Gee, my stupid. It was really hard for me to read a whole page of text.. or I didn't understand it?

Perhaps I should have asked the question as " Is this a good choice for my AR or should I spend the extra money for an new unit that is better suited for my set up. "?

A simple “ Yes, that will work fine on your gun” was all I was looking for prior to spending 700.00+ dollars.

As far as "everyone else here should just take the time to answer your question" I thought that’s what a forum was?  Thanks again for "taking the time " to make me feel welcome here as a new AR owner.