I am thinking of going with Trijicon ACOG TA31RCO-M4CP for my LWRC M6A2.
http://www.militarywarfighter.com/Trijicon_TA31RCOM4CP_p/trijicon-ta31rco-m4cp.htm
I like its reticle pattern.
However my barrel is 14.7" and with the muzzle break its about 16". It's says on the website that is was calibrated for the M16M4 rifle with a 14.5”
Will I be safer to go with the TA31F that only specifies that it was calibrated for 5.56(.223 cal) flattop rifles????