Varminterror
Member
- Joined
- Jul 17, 2016
- Messages
- 15,068
They definitely should have done this on the SPC case family. The comblock case family is a scourge for ARs, especially at high pressure.
It’s been done in multiple iterations, the 6-6.8 variants are out there, and they can’t deliver the same performance with the heavy, high BC bullets. The 6 WOA, 6 Hagar, 6 PDK, 6-6.8, and 6 DTI are examples. Long ogive bullets don’t fit within mag length. I’ve thoroughly enjoyed the 6WOA (and 6-45) with lighter bullets for coyotes in the past, and the blistering speeds with 75-87grn bullets are great for short to mid-range shooting. But they give up a lot of speed quickly compared to the high BC 105+ pills.
The 24 Nosler is the only case I have seen which pushed the SPC shoulder back to fit the heavies into mag length, but there simply isn’t enough case capacity left when you give up that length in the skinnier SPC case. That was the failing of the 24 Nosler (well, one of its failings at least) - they trimmed the SPC case back to 1.6”, which still didn’t fit most of the 105+ bullets into mag length, and the result was terribly anemic. The skinnier 6.8 SPC case might reduce bolt thrust, but it gives up too much capacity when you make room out front for long ogive bullets. They tried to push the pressure up to make back the difference, but it didn’t pan out. The 24 Nosler has almost 25% less case capacity than the 243LBC/6mmAR, despite a 10th inch longer case. I expect still over 20% less than the resulting capacity of the new 6ARC. As @Gtscotty noted - even at higher pressure, the smaller 24 Nosler case fell short of what we’re seeing with the 6 Grendel variants (although incorrectly citing the 24 Nosler as the “exact critter,” since it’s considerably different in many ways). Running 2300-2400 with the 105’s is pretty lackluster. For lighter bullets which fit into mag length, the 6-45 has larger capacity even than the 24 Nosler, and of course, doesn’t require special mags or bolts, or sparsely available, expensive brass. The 24 Nosler was a non-starter.