I'd scratch the 2.6" box as I think you'd just wind up with something close to a Model 7, and it's really not needed for the Grendel/PPC based rounds that would be it's bread and butter. There are other options already if you want a .223 or BR/Dasher. I'd just make 2 versions, one with internal feed lips for ADL/BDL, and one without for the proprietary scaled-down AICS style mags and bottom metal that would have to be designed. I'd probably scratch the AR mag compatibility. Find a company to contract out a couple of stocks designed for the action, a lightweight hunting model and a heavier target version.
