The Geissele Super Modular Rail (SMR) MK4 handguard is a lightweight free floating rail system designed to be versatile and allow the user to easily tailor the platform to his or her unique needs. Accessories can be mounted at the 3, 6, and 9 o'clock positions as well as the upper 45 degree quadrants via Magpul's M-LOK mounting system. The top of the handguard has a standard Picatinny rail interface the entire length of the handguard. The rear sides of the handguard also feature QD sling mounts. The SMR's lower 45 degree quadrants allow maximum heat dissipation from the barrel and also reduces the rail's overall weight. The SMR features Geissele's 2" long barrel nut to provide a stable and rigid platform for the rail. This increases accuracy and zero repeatability during disassembly and reassembly when performing maintenance. Barrel nut wrench sold separately.
The MK4 has permanently attached QD sling mounts and Picatinny rail sections on the front sides of the handguard. The MK8 does not.
Inside Diameter: 1.35"
Outside Diameter: 2.11"
Installed Weight (w/ Hardware): 11.0 oz.