I recently changed the mounting method for my TA-31 from and ARMS#19 to carry handle mounted.   In a brief trip to the range the other night it seemed that this method will work fine for me.  

I really like the idea of being able to shoot irons under my ACOG. I just plain enjoy irons sometimes.  Also, the police department I work for is in the process of approving a personally owned carbine program and they may require access to both aperatures. My problem is that I can't reach my A2 sight to change the aperture.  What is the solution to this?  Am I missing something really obvious here?  Thanks, dg.

Fair warning, In a carry handle mount, you need to torque down the mount screw and apply some blue loctite to it or it will eventually work loose from vibration of shooting and the ACOG point of impact will begin to walk.

My solution when I had a carry handle mounted ACOG was just to leave the large aperture up. I reasoned that anything requiring immediate application of iron sights was close enough that the large aperture wasn't a problem and it could also be used in low-light. Problems far enough away to require the small aperture were also far enough away to disengage and fix or discard the primary sight (ACOG).

B_R echoes my thoughts exactly (you ought to consider therapy if that happens again, bud!).

So is it "Great minds think alike" or "Fools seldom differ" that applies here? [:D]

Thanks guys-  I suspect our ordnance guys will have me use the iron sights for qualifications.  The specs for acceptable optional optics appear to be describing co-witnessed eo-tech's and aimpoints.  It appears that if the iron sights are functional while the optic is used it is acceptable.  Not sure if that means I can use my arms #19/#40 setup so I want to have a "plan B" in my bag.

Also, I tried to "what if" this deal to predict when I might come up with a reason to use the small aperture irons  with an acog available, that sure didn't go far.  Still, it seems like it would be nice to be able to use everything you have available equipment wise.

That being said,  I can't yet say that I prefer one mounting method over the other.  I'm not sure I won't personally prefer the carry handle method. Having used both, (and apparently no longer using the carry mount method, a clue for me!), could you guys hit some pro's and cons of both?  

I'll say up front that I have not found the additional height of the carry handle mount to be a problem, it has not seriously exxagerated hold over for close in shooting and I shot some repeatable, tight groups the other night so mounting the rifle against my chin as opposed to my cheek apparently is not a problem.  

I appreciate your thoughts, it really helps me sort this stuff out.   dg.

In my case, I had a TA11 mounted to a A2 receiver. Like you, I had no issues with height or use in shooting. Close-in it was a little more holdover than I wanted to deal with; but I could have learned to live with it.

My major issue is that with the TA11 mounted in the handle, the rifle didn't fit any racks or cases.

Also, I found no way to remove the scope and reliably return it to zero (i.e. during cleaning or to fit it into a case or rack). Since I had an A2, I couldn't detach the entire carry handle and had to remove the scope by unscrewing the mounting screws.

At first I found I could get a not-perfect but usable RTZ by torquing the screw handtight and then 1/4 turn with an allen wrench. The downside here is the mount would work loose and start to walk after about 100 rounds.

I was able to tighten the mount enough to stop it from working loose; but I wasn't able to get RTZ that way as I couldn't torque it the same way every time.

Ultimately, I went with a new flattop receiver and ARMS #19S + ARMS #40 with that rifle as I had always planned to originally. I really seriously considered not going the flattop route since except for the issues noted above I was having good luck with the A2 mount.

However, I do like almost all aspects of the flattop mount better. The ARMS #19S is simply amazing in its ability to securely mount and return to zero. I flip that thing on and off the rifle like a light switch and it is always perfect. The ARMS #40 is a perfectly good iron sight that fills its role nicely.

I did like having the ACOG mounted higher on the carry handle, particularly close-in since I have a bad habit of looking over the top of my sights at close ranges (focusing on target instead of sights). The correct thing to do would be to retrain the user to properly utilize the sights; but it was nice that the ACOG was sitting right where I had habitually looked and was in perfect position to use it. With the BAC feature, I found that quite useful.

When you looked over the sights, did you still hit the target?  When I shoot hand guns up close and fast, I bring the gun up in good two handed form, but my focus is on the target area, and I always hit low.  But I am still a newbie on the handguns so I will get it sometime.  Cannot say that I am not happy with myself as up close I can just point the gun and go bang! and almost hit it.  I would imagine that it will come with practice.

I have my TA31 mounted to a removable carry handle, so I don't have the RTZ difficulties B_R described.  I applied some blue locktite to the ACOG mounting screws (I went with the factory-recommended two screw set-up) to prevent them from working loose.  I can swap from carry handle/ACOG to my Leupold VariX-III (in an Armalite one-piece mount) and back with no appreciable loss of zero.

Regarding the iron's apertures, one thing you might try is a simple "hook" tool: use the bent end to pull the up aperture forward and use the straight end to push it down.  Granted this is not a technique that I'd recommend when you're "in the sh*t", but it should work on the qual range.

With the rifle I would hit low, usually as a result of not enough holdover. With the pistol, I would usually hit high.

I think I've broken myself of the habit for the most part on both pistol and rifle, although I occasionally revert when I stress.