What was your idea?
The Dissipator ahs been around for a while. 16" barrel with rifle gas system and some versions with carbine systems and rifle length hand guards. Short barrel with long sight radius and more heat shielding to "Dissipate" the heat was the original marketing on them. Bushmaster and DPMS made versions and had a law suit over who could use the name Dissipator. The gas sytem shouldn't have much to do with the velocity. Right around 3000-3100 FPS is about normal for a 55gr load. A 20" barrel would get it up to about 3250-3300 FPS.
Some folks ahve had cycling issues with rifle length gas systems on carbine barrels in really cold weather, but that is about the only negative I have seen along with some ammo sensitivity for lower powered rounds. This can sometimes be corrected with a lighter buffer or opening up the gas port a bit to get more gas into the system to compensate for the reduced dwell time that results form having the port so close to the muzzle.
Enjoy the set up, they are really sweet to shoot. I've been a "Dissy" fan for a long time