Geissele Automatics SMR MK4 13.5 in Super Modular Rail M-LOK

Description

The Geissele Automatics Super Modular Rail (SMR) MK4 is an ultra-lightweight free-float handguard designed for AR-15 platforms. It uses M-LOK mounting slots along the 3, 6 and 9 o’clock positions and the upper 45 quadrants for accessory attachment. Integrated short M1913 Picatinny rail sections are located at the fore of the handguard in the 3, 6 and 9 o’clock positions for direct accessory mounting. The SMR MK4 emphasizes ventilation and reduced weight while maintaining a rigid mounting platform for optics and accessories.

Key Specifications

• The finish is Black.
• The overall length is 13.5 inches.
• The construction material is Aluminum.
• The handguard uses M-LOK attachment points on the 3, 6 and 9 o’clock positions and upper 45 quadrants.
• Integrated fore rail sections are M1913 Picatinny at the 3, 6 and 9 o’clock positions.
• The product is designed for AR-15 platforms.
• The design is a free-float rail intended to maintain a straight mounting surface along the barrel length.
• The rail features extensive venting for heat dissipation and reduced weight.
• Includes Geissele’s proprietary long barrel nut to increase surface contact where the rail interfaces with the receiver.
• Installation requires a Geissele barrel nut wrench, which is sold separately.

The SMR MK4 provides a versatile, lightweight platform for modular AR-15 builds where accessory placement, repeatable zero and reduced weight are priorities. Its combination of M-LOK slots and forward Picatinny sections lets builders configure a straightforward, no-nonsense system for optics, backup sights, and ergonomic accessories while keeping the rail rigid and well-ventilated.

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