I have no experience with KeyMod, but I installed a Magpul M-Lok hand guard set and some M-Lok accessories (5-slot rail and an AFG adapter) on a Colt carbine yesterday. The M-Lok just didn't seem to work correctly right out of the box. If I had insisted on not taking the hand guards off to install these, I'd still be in my workroom trying to get it to work. The cam nuts didn't engage in the M-Lok slot, in fact, they kept on spinning, which meant the screw couldn't gain purchase and keep threading until tight. I made sure that the spacing was correct, and that the cam nut was in the slot with an opportunity to seat itself. I had to gain access to the backside, grab the cam nut with a pair of needle nose pliers, turn it perpendicular to the M-Lok slot so it would lock, and then tighten the screw. Had to do that with all four cam nuts. It's very secure now that its installed, but I'm less than happy with the way it performed. Maybe non-polymer hand guards or slots will perform better, but can't say I'm in a hurry to try. Should have went old-school and stuck with the MOE versions. At least with those I know what I'm getting myself into.