Considering a new AR caliber

[320pf]

I've already got mags for the 6.5 Grendel and of course 5.56 AR (which will work with many of the other variants discussed) and of course I've got brass and dies for 6.5 Grendel, 5.56, and .300-221 - I've been reading good things about 12.5" barrelled 6.8s as well.

If you have 6.5 Gren brass and dies... I would go with the Grendel

[greywolf2112]

Sorry if I am miss understanding your reply. But the case head diameter of the 6.5 Gren is 0.445 inches and the 6.8 SPC is about 0.420 inches. Hence, both the 6.5 Gren. and the 6.8 SPC require their own special bolt/carrier group and mags.

The variants based on the 223REM all use the same bolt/carrier and mags as the standard AR.

No problem - small misunderstanding. I have no extra bolt or carrier in any caliber, so I'm going to have to get those parts regardless.

[Todd.K]

If you can get good 6.5 hunting bullets the the weight range you want I don't see much reason to change. I know there are a bunch of good choices for the 6.8 in the 100-110gr range, I have only looked at and used 140gr bullets in my .260 so far.