'Way back in late Twenty-hundred-and-aught-six, I built an AR carbine in 6.8 that makes me look back and cringe now...
For instance, all that nice hardware? Nearly two grand in accessories, had everything been bought at new retail? It's clamped to a DerPMS 6.8 SPC upper. ("DerPMS" shamelessly stolen from pdb.)
And that big ol' GG&G VFG is way too far back by the magwell to be of much use for anything other than horsing the gun around in full auto, which this one is not, derpy Superior Arms receiver markings to the contrary. That far back, the grip can't help stabilize the gun much while shooting on the move or transitioning between targets, and it gets in the way if you try to hold the gun any other way than using it.
If that thing had three magazines through it when I sold it, I'd be shocked.
And here is the carbine put together in late '12. I'd already assembled the lower when the Great AR Panic occurred, and so I went to Bravo Company's website and ordered the upper. Even though the Very Smart People to whom I listen on the matter of ARs all prefer the standard carbine length gas system, I got a midlength, partly because beggars couldn't be choosers at BCM that cold December morning, and partly because I wanted to at least try a midlength for myself to see what the fuss is about. The optic is an Aimpoint PRO, which is about the best bang for the buck in good electric glass today. (My next gun will have a low-power variable, though, probably a Burris MTAC.)
The AFG is out where it's of use when using the whole straight-arm c-clamp grip thing*, but doesn't interfere with moving your hand around on the gun to other holds. The stock was on sale, but Vltor makes a good stock, so although I may replace it, I'm in no rush. Fixed iron BUIS from Daniel Defense with an "A1"-style rear minimize the chances for the irons to get knocked askew and have a bottom-third "co-witness"† through the Aimpoint. The 12" rail farm from LaRue wouldn't necessarily be my first choice either, but it's what BCM had, and it's wrapped around a MP-tested 1:7" chrome-lined tube.
I'm happy with it so far. I wonder what it will look like in 2019?
*aka "The Magpul hero grip". Which is why the remote switch for the SureFire Mini Scout light is where it is.
†Which isn't actually a co-witness at all, but everybody uses the term so what the hell...