So, what should be my next AR upper?

[grey2112]

OK, I'm thinking of selling my 9mm AR upper (8" barrel) and going another route.

My criteria: Accurate, reliable, can be reloaded (ammo) relatively cheaply, would be nice if I could use standard mags but have no problem buying proprietary if I need to (if I don't already have mags that will do the trick), uses a regular AR-15 lower.

I already have brass and dies for all of my current calibers.

I do NOT have an upper, bolt, carrier, etc. yet for the new project, just a complete lower.

I want it to be a rifle with good short and medium range capabilities (especially in terms of energy delivered on target - I'd like it to be good for hunting medium sized game and hogs, with good defense/anti-personnel uses if TSHTF).

I'd like to go with a 14.5" - 16" barrel max.


Here is what I already have:

.300 BLK in 16" (soon - TP555 working on that)
.300-221 in 8" (will probably convert to .300 BLK)
5.56 in 16"
5.56 in 14.5"
LaRue OBR 18" (heavy sucker)
6.5 Grendel 20" (somewhat heavy sucker)

So, would I be best served with just another, much lighter weight 16" or 14.5" Grendel? Or is there something else out there that might be in the cards?

I've seen arguments for/against the following:

6.8 SPCII
.25-223
6.5 MPC (SSK proprietary)
6x45
6.5 TCU-AR