BTDT ...
I thought the 6.8 SPC cartridge would be nice as a versatile "ONLY ONE AR" caliber.
And maybe,
down in the US,
where they can get ammo for it and hunt with it,
the 6.8 makes some sense.
BUT,
here in Canuckistan,
it doesn't really work out too well.
After playing around a bit with a very nice brand new RRA 6.8 AR,
and having a LOT of trouble finding 6.8 ammo,
I sold the RRA 6.8 SPC upper, all the 6.8 mags, and 5 boxes of 6.8 ammo.
I kept the RRA lower,
with a really nice match trigger,
and dropped on an LMT 10.5" upper in 5.56/.223.
Then I picked up an AR 10/R25 in .308,
and was back in the game with all my bases covered by the much easier to find ammo for .223 AND .308,
for a LOT less aggravation with trying to find UNOBTAINIUM 6.8 SPC ammo.
If 6.8 ammo was readily available here in the North,
I'd still seriously consider the 6.8 as it is a nice compromise between power and size.
But IMHO, for several reasons too complicated to go into here,
.300 Whisper or 7.62 Russian both might be better choices in an AR.
But as it is now,
I'll stick with my TWO ARs in .223 AND .308.
YPMMV
{:{)
LAZ 1