Geissele 10" M-LOK MK4 Federal Black Super Modular Rail 05-430B

Geissele 10" M-LOK MK4 Federal Black Super Modular Rail 05-430B is the same rail built under contract for the FBI - not a civilian-market variant of it, the actual thing, just available outside government channels.

Machined from 7000-series aluminum and Type III hardcoat anodized, this Geissele SMR MK4 locks to the receiver through Geissele's proprietary barrel nut, which extends surface contact well beyond a standard nut's footprint to keep the rail from shifting under recoil. A full-length M1913 Picatinny rail runs the top at 12 o'clock, with an extended section at 6 o'clock and shorter sections at 3 and 9 - elongating the bottom rail specifically to accommodate bipods and other accessories more comfortably than a symmetric layout would.

This MK4 handguard's M-LOK slots sit at 3, 6, and 9 o'clock plus the upper 45° quadrants, and maximum venting cuts weight down to just 10.2 ounces bare, 11.8 with the barrel nut installed. That's light enough to notice on a build without sacrificing the rigidity that made this rail worth putting under federal contract in the first place.

Key Features:

• 10" free-float length, full-length Picatinny top rail
• M-LOK slots at 3, 6, 9 o'clock plus upper 45 quadrants
• 7000-series aluminum, Type III hardcoat anodized
• Proprietary Geissele barrel nut for extended receiver contact
• Elongated 6 o'clock Picatinny section for accessory clearance
• Weight: 10.2 oz bare, 11.8 oz w/ barrel nut
• Inner diameter 1.35", outer diameter 2.11"
• Fits mil-spec M4/AR-15 upper receivers

This Geissele MK4 Federal rail delivers the same proven strength and modularity currently issued under an active federal contract, in a compact 10" package.