The subject line says it all.  What's the optimal 3x24 comp ACOG sighting distance using Q3131A?

According to Armalite, after a four-month (I repeat:  FOUR month) wait, my 16" mid-length flattop pre-ban upper might (I repeat:  MIGHT, as in maybe, possibly, could be, chances are, in theory, seemingly, and apparently) be ready to ship this week.

Optic is mounted on a #38/19S combo.

Thanks for any replies.

On a flattop, such as you are doing, 50 yards is optimal.

On top of the carry handle (particularly for the 20" barrels) 75yards is better.

Thanks.  Next question:  When sighting at 50 yards (as opposed to meters), at what distance will the 55-gr round again meet zero (i.e., the target plane on the downward arc)?  What will max apogee be on the round (i.e., how high above zero will the round soar before beginning its descent to plane again)?

Thanks again for any replies.

I'm not sure of your height over bore, so I'm going to use iron sights to give you an approx. answer.

Assumptions: 55gr, 3260fps, BC = 0.243, 2.6" above bore

The zeros are at 50yds and 242.6yds.  The maximum path is 2.27" at 151.9yds.

Sweeeet, Raider.  You the Man.  Thx.

Rifleman,
let me know how it goes and how you like your TA50.
I just got one (TA50-2) and sighted in 16" bbl A2 carry handle mount @75yd per the advice here.
Worked out well.
After needing only two windage adjustments, I settled on 1.5" group w/3131A at the triangle tip. Now it's wicked fast and accurate dead-on C.O.M. wherever I put the triangle body out to 150 yd that I've shot so far.
Simple to mount, sight-in and use.
A remarkable optic this is.

Have fun!

HOB will be around the same as the irons so 2.6" would be fine (its what I use).

However S.R. used the velocity figures for a 20" - with your 16" the far zero would be around 200M (218 yards) with a max height of 2"
(not too far different from the 20").

Revised post for 16" velocity.

Assumptions: 55gr, 3132fps, BC = 0.243, 2.6" above bore

The zeros are at 50yds and 226.7yds. The maximum path is 2.03" at 142.4yds.

Thanks again to everyone for the info.  If Armalite is telling me the truth (not their strong suit), then I'll be shooting w/in a week or two.  I'll report back w/ general impressions asap.

BTW:  For those using comp ACOGs, has anyone tried mounting their 19S backward (levers on ejection port side)?  Doing so gives the comp user a significant amount of eye relief advantage, as the scope can be mounted in the forward hole of the mount (now the rearmost hole) and thereby move the scope back appx 1/2".  If anyone's tried it, have you noticed any problems w/ ejection or anything else?

Thanks again.

I unintentionally tested that bassackward mounting method with both a #19 and a #19s, it mounts farther back on the rifle against my arms #40 best with the levers on the left side (opposite the ejection port).

When correctly mounted, eye relief was equal with both mounts. Its perfect now, I was having a little trouble with eye relief when I had the mount backwards, my ta-31 was too far from my eyes.

I had a 19s for a day but liked the secure feeling I got with two levers. That's probably just superstition though, and the 19s really LOOKS nice.... dogguy  

*Edited to add-  I now realize that you were posting about compact acogs- guess I'm the dumbass!  BUT, I can tell you that I had no ejection problems whatsoever when my #19 had the levers on the right...... good luck, dg