2 rail. I've shot 18s with rifle fuel like how smooth and accurate These are. I can put extra money into effectiveness parts then clone proper pieces like a ops brake and collar that I haven't got a can for. Higher Energy matches replicate the USMC Table one qualification shoot https://kacquadrailcarbine41727.newsbloger.com/30067918/the-best-side-of-knights-armament-carbine-length-quad-rail