bwaites Wrote:2.30 doesn't gain enough space to justify a whole new magwell and specification...That's true. But, the reason for the new mag well is the need to accommodate a P-Mag designed for the fatter 6.8 SPC cartridge case. While they were at it, they took the opportunity to increase length enough so that SPC II ammo (such as offered by Wilson Combat) could also be used.
Being able to use 2.30" loads is just a nice "plus" that could be incorporated with minimal effort and expense. To go longer would entail a much more extensive redesign of both upper and lower receiver assemblies, resulting in an "AR-12.5" platform.