Very interesting project I'm working on.
Basic idea is to create BEST possible MISSION CONFIGURABLE AR-15 in multitude of calibers and options within limitation of the base platform. One of the most important things I identified is an ability to quickly change barrel/bolts. MGI QCB upper was chosen for this task. This upper allows to rapidly change barrels and bolts and you choice of caliber is limited only by your lower. MGI also working on modular lower which will allow you to use different mag wells. Another nice thing is you could easly take down you rifle and but it in the briefcase - longest part is 14" - and reassemble it back in under 1 min. I have not tested upper extensively yet but so far it holds zero on the barrel between changes. So the choice of the barrels/calibers from top to bottom
223 20" Douglas Premium HB
223 Ackley Improved 24" SuperBull and 16"
Medium done by John Noveske - best barrels I've seen
6PPC 24" SS Match barrel
6.5 Grendel 24
SuperMatch by Accuracy System - great barrel as well
6.8 SPC 20" by ERSHAW
7.62x39 20" by ERSHAW and 16" Colt
440 Corbon Magnum 18" by Tony Romix
I'm also getting 18" 458 SOCOM and 16" Carbon Fiber 223 AI.
But barrels/bolts cant function by themselves - so here is a rest. Bushmaster lowers with ACE SOCOM stocks - M4 and full length with cheek piece. Williams set triggers should be done soon. - Right now Jared on the CQB (M4) lower and 2 stage Armalite on another. Premium springs all around, bolt upgrade kits, JP ant-walk pins, MGI recoil buffers, MAGPull oversized trigger guards (need to install), Ergo Grips, Arms raiser. Tell me if I missing something. ;) Streamlight M6, Harris Bipod on the ARMS QD mount, and some forward grip, everything is QD for fast configuration.
Scopes. - Burris Black Diamond 3-12., IOR CQB 1.1-4 Lighted, Cobra Holowsite and Aimpoint - all QD. - Use my own system for Quick Zero.
Here it is with in CQB 440 Corbon Magnum configuration
And 7.62x39
Magnificent 6.5 Grendel with "sniper" configured lower - I'm still waiting for riffle length barrel protector
Ultimate varminter - 24" 223 AI with sniper lower
20" 223 Barrel on.
