I prefer the 300AAC blackout. Works well on Kentucky whitetail super and subsonic. Built on a palmetto state upper and lower with guts from midway. Simple as pie with no need for special tools but they do make life easier.
Since then i have read that folks are having good luck with a subonic 6.8 spc with a 1:7 twist barrel. Military is suppose to be going to a non-spc 6.8. I’d wait on any new ar’s until we see what they got.
Not a huge fan of the 223 but it’ll do in a pinch.
Agreed, it will work fine. (My post was just a lame joke on my screen name). I have zero against smaller caliber weapons.
The military has been playing with the 6.8 SPC from Remington since I first fired an Australian F89 Minimi in that chambering in early 2000, its primary consideration being the arrangement of suitable links for feeding in full-auto SAWs and in the then-popular H&K XM-8.
Of late, SOCOM has given the .300, often silenced, a good workout, especially with night scopes, and has reportedly made in excess of 1000 kills in Afghanistan and Syria with it. It's main disadvantage is its ability to have the .300-diameter bulleted cartridge chamber in a regular 5.56mm M4, pushing the bullet back into the cartridge case and then firing, the .30 bullet NOT going down the smaller diameter barrel. Special Forces and other SOCOM users are well-enough trained that this is not usually a problem for them, but general service-wide issue would be too likely to cause problems. The 7.65 Wilson is an improvement that avoids this, but though it too is being tried, it's still a test case.
And then there is the .350 Winchester Legend. Too new to tell, but offering promise, we'll see. I want one with a gas-operated piston system in an AR-18 upper.