Mark, you may very well be right. My experience with a cut-down rifle barrel was the opposite; it wouldn't run unless clean, freshly lubed, and with hot ammo.
Two thoughts on that - first, I believe that both the pressure and the duration are in play there, so it's not a matter of sufficient pressure alone; and second, I'm not saying the recoil would be more significant than a 11.5"/carbine setup. Maybe it wouldn't even recoil quite as much. What I did intend to convey is that the recoil wouldn't be appreciably less than the equivalent barrel length with a carbine gas system, in which case you would have sacrificed a measure of reliability without gaining an worthwhile trade-off in recoil characteristics.
Is it a piston-operated system? If so, it's interesting that they chose the middy position for the gas port, but I'm not sure it's apples-apples to compare it with a DI system. In a short-stroke gas piston system it's got a much smaller volume of gas needed to pressurize the piston chamber and force the op-rod rearward.

