I have a Colt 6721 I bought three years ago that I have shot a bit, but I havent used much lately as I dont like the carbine length handguard. I was thinking of selling the upper and building something mid-length, when my friend Andrew Brady at Lone Star Armory in Ft Worth mentioned he had a 15inch EMRV2 in stock. I had him shave the front sight and he installed the EMRV2.
It's like a whole new rifle now, one that I am enjoying shooting. Its also lighter than when it had the carbine length MOE and full front sight tower, or at least it feels that way. Currently a Trijicon Accupoint 1-4 in a Trijicon (Bobro) mount sits on it. I'll get it sighted in to decide if I want to stay with the Trijicon or go Aimpoint, then it will get a light and sling.