so i'm looking at 'battle scopes' and come across the new TA31RCO-M4 ACOG for the 14.5" M4 barrel in .223

how OFF do you think this will be shooting 6.8 out of a Barrett 16" barrel? Anything remotely close to what it's intended to do? It will be mounted on a flat receiver.

i originally thought a .308 reticle ACOG 5.5x50 would suit this cartrige better, but i can't find anyone with one in stock if my life depended on it...actually i did find one but it was in .223 not .308

i do like the ACOGs just don't know if it's a waste of time going with that scope on that gun/caliber

who uses what on their 6.8's?
no electronic sights? what's compatible?

If I zero at 50 yards. It is about 1 inch high at 100 meters and within about 1 MOA out to 500 hundred meters.  I am at 4500 feet shooting a 110  Vmax (.370BC) at a little more than 2550 fps.

What is your elevation?  That will make a big difference.  

sea level...FLORIDA.

i'm saying...if i mount a 31f lets say, onto the 6.8 16" barrel, and sight it in for 100 yrds. at the tip of the chevron reticle, how close if any will the 6.8 balistics of the round be on a .223 reticle

i'm thinking i should lean towards a .308 reticle more than a .223 thinking the 6.8 is closer in trajectory to the .308, problem being the only .308 reticle made is the ta 5.5x50 which costs $1500 and can't be found.

i didn't want a big tube atop my 16" barrel but...i guess i'll wait 'till someone comes out with a 6.8 reticle if at all.

not sure which model it is, but Trijicon does a TA11 w/.308 calibration.  they also do a TA01 variant in .308.