6.8 And Barrel Length/Upper Selection

[Leatherneck556]

This could potentially be better suited for a rifle-related forum, but I'm primarily interested in talking about 6.8 uppers from a perspective of maximizing the external and terminal ballistics of the 6.8 SPC round.

I'm seriously considering taking the plunge of getting a 6.8 upper to put on my lower - train with 5.56, fight with 6.8.

My main questions are these:
1. For use as a "general purpose" cartridge from 0-400, what would be the "ideal" barrel length? I'm assuming based on the 6.8 mm Ammunition Choices sticky that 16" would be a good length. Maybe a 14.5" barrel though? I dont' know. My preferred optic setup for a general purpose AR is an ACOG with an offset mounted T1 Micro. I would like to have the trajectory match pretty close to an ACOG TA11 or TA33 (I know they don't make a specific 6.8 ACOG in those models - only in TA31).
2. Who makes the best uppers currently? When I talk about best, I think reliability and features that a military gun should have - Chrome-lined with SPC II chambers. Direct gas instead of gas piston. Preferably a mid-length setup (if 16" is the way to go).

I apologize if this thread isn't appropriate for this forum, but I appreciate any help.

[DocGKR]

For what you are describing, any barrel from 12-16" would work well. I'd likely put a Battle Comp BABC on it, unless you are going to go suppressed. MSTN has been building 6.8 mm uppers longer than anyone else. Noveske also makes a good one.

[Clint]

For general purpose use, especially considering your stated 400 yards range, a 16" midlength DI is the first choice.

In the NFA category, the 6.8 maintains quite good velocity down to 12.5" barrel length, especially with the 85 tsx.