We do dig the drills of T.Rex Arms and Garand Thumb as seen in their videos. But what is their favourite rifle? They talk about why they like their compact MK18s that you see in the video. MK18s are basically the CQB Receiver modification on the M4 rifle done by the NSWC in which... "Lucas Botkin and Garand Thumb delve into MK18s and the equipment they stick on these shorty rifles."