I tried out the ARMS 16A mount on an M16A1 with a M2. Hated it. The height-over bore makes close range shots impractical. Inside of 15 yards it required floating the red dot over the targets head to hit the center of the head. I am faster and more accurate with the A1 sights than I am with the chin weld ARMS set up at any range. On a carbine with a collapsible stock it might work adequately for fast COM shots, but that's about it. On a full length rifle with a fixed stock awkward is the best word I can think of to describe it. If you're still interested after my glowing review check the EE, there are a couple posted there
.
On my personal gun (LMT Defender 2000) I have used the M2 in a Larue LT-150 mount and it worked as expected. I like it so much that a Micro T-1 just appeared at my house. I am going to try out the Aimpoint gooseneck/QRP package on my work gun in the next week or two. Personally I think the gooseneck mounts look ridiculous, but IMHO proper function is more important than appearance.
I'll update after a day at the range in a week or so and post pics of my work gun. The fit & finish crowd is going to explode. It is a 40 year old Colt M16A1 with uneven front sight ears, a gray/black/raw aluminum mismatched finish, and the lower and upper are the loosest I've ever seen. Works like a champ and is more accurate than I am.
IMHO anything mounted on the carryhandle adds too much height over bore, a terrible chin weld, and this cancels out the advantages that optics offer over your irons.