You can probably see where this is going. I'm wanting to have an AR upper with performance close to a 6.8 SPC that I can use normal in standard PMags.
I'm not 100% sold on the .300 Blackout as I think that's a little too heavy of a bullet to be pushing with the volume of a 556 brass.
There HAS to be a round in between the 223 and the 300 based on the NATO cartridge diameter! Right?
I'm not worried about ammo availability as I would just reload. But of course I would need bullets...
I wish they would have used a standard diameter case when they made the 6.8 or 6.5.