First, thank you to Tony and everyone on this thread. I rarely have time to post but have garnered so much knowledge from reading this thread over the years. I finally took possession of my Colt M16A2 last week (can someone email me a link on how to post pics?). Such a joy to shoot.
Currently I’m running a set of LMT MRP uppers.
11.5 with aim point micro
14.5 with irons
16 with nothing so far.

So to the question, I’ve never shot full auto with a magnified optic. Was thinking maybe a low power ACOG for the 16”. Can someone with more experience weigh in as to what they find practical? I’m hoping to shoot steel on a bipod at 100yds and also shoot offhand with this upper. Somewhat of an IAR type upper concept.

A LPVO is nice for a IAR setup. Something like a 1-6x provides some magnification, gives you large field of view, and can be used more like a reddot on the 1x setting.

I had a TA44 on my SP1 carry handle for a while. Lets you use the iron sights as well. Tiny little acog, great for old eyes

I use an Aimpoint with a Aimpoint 3X magnifier on a Larue Flip to side mount.

I haven't tried it, but anything magnified is going to be difficult to view during a Burts/Full Auto.

Heavy barreled M16s like the M27IAR or Colt LMG are actually very controllable in full auto if you use a bipod, even more so with a muzzle brake or suppressor.

Mine is a 11.5"...it dances a bit

OP's uppers listed are on the lighter shorter end of the spectrum.

yeah you need a lot of weight at the front end of the firearm.

I'm in the process of building a LMG / IAR setup of sorts and am planning to use either a 16" or 20" heavy profile barrel. The heaviest chrome lined barrels I could find were from RRA.

20" Heavy Barrel w/ Rifle Length Gas System - Weight = 58 oz
16" Heavy Barrel w/ Mid-length Gas System - Weight = 48 oz

FWIW your 11.5" barrel probably weighs about 20-25 oz. You then also get more weight from the longer rail and you can add weight with a heavy muzzle brake or a suppressor.

Also just dial back on the magnification, which is another advantage of the LPVO, you can put it at 6x for precision semi-auto, or back it down to 1-2x for full auto.

Thanks for the input everyone. I will look at LPVO. Any recs are appreciated. I plan on looking at lower power options (low power ACOG) as well. Going to run it hard this weekend. Will try to post some pics.

I've been thinking about a PSA upper w/heavy barrel and low powered optic for my M16.  Would shoot it off a bipod or MG42 tripod.

https://palmettostatearmory.com/psa-18-chf-heavy-barrel-mid-length-15-precision-lightweight-m-lok-upper-no-bcg-ch-516444448.html

I am starting to use the sig arms Romeo.  working pretty good and loving it
Guaranteed for life and cowitnesses will with iron sights