KAC M4 Carbine Rail Adapter System Assembly (RAS)

KAC M4 RAS 5.56 Rail – Military-Proven Drop-In Quad Rail

The Knight’s Armament M4 RAS (Rail Adapter System) is one of the most battle-tested handguards ever fielded, with over 1 million units issued to the U.S. military. Designed for the M4 Carbine, this rugged, non-free-float, drop-in rail system is a major upgrade over standard polymer handguards. It features full-length, Mil-Spec M1913 Picatinny rails at 12, 3, 6, and 9 o’clock, offering rock-solid mounting for lights, grips, lasers, and other tactical accessories.

Unlike most 2-piece quad rails, the M4 RAS securely clamps to the barrel nut with a screw-lock system for enhanced stability and zero retention. Includes (3) KAC 11-Rib Rail Panels for added grip and protection.

Compatibility Requirements:

• Carbine-length gas system
• Delta ring assembly
• Fixed front sight/gas block
• Round handguard end cap
• Best suited for M4/Government barrel profiles; heavier barrels may require minor fitting
• Compatible with AR-15/SR-15 platforms (not SR-25)
• Installation instructions included

Specifications:

• Weight: 8.9oz
• Length: 6.25″
• Free Float: No
• Material: Aluminum
• Finish: Black Anodizing