The short barrel doesn’t kill the SPC like it often does most 6.5s and smaller bores.
That's a common theme the 6.8 fans like to repeat, but it's not really true. The 6.5 Grendel does just as well with shorter barrels as the 6.8 SPC. If we're going short, I will (and do) take a 12.5" 6.5 Grendel over a 12.5" 6.8.
....and inside 400, it won’t matter. You’ll generally burn a bit more powder in the grendel. I just find the spc easier to deal with in ARs, though I’m a 6.5 fan. If I only loaded, and didn’t care about some other stuff, I’d probably run the SPC case necked down to 6.5. If it’s a bolt gun, grendel or CM, or bigger, all the way.
