Geissele Automatics was established in 2004 as a manufacturer of trigger mechanisms for the AR-15 rifle. Gesssele products quickly became the trigger of choice for M4 carbine based weapons by many U.S. Special Forces entities. Rely on Geissele when you expect superior performance, quality, and reliability.

The Geissele Automatics Super Modular rail MK4 was designed to be a lightweight modular rail system that also provides you with Magpul M-LOK attachment points in several locations along the length of the rail. The MK4 features an ergonomic design, with a flexible and modular set up procedure. The free floating design is strong and rigid, and features an integrated M1913 Picatinny rail section at 3, 6, and 9 o'clock. Accessory rails are easy to install and do not require a gunsmith. However if you do not have the required tools or mechanical know how you should seek the help of an expert. The SMR MK4 also features Geissele's proprietary 2.25" long barrel nut. This increases the surface contact where the rail interfaces with the receiver and creates a platform that can be trusted to be straight and true the entire length of the free float rail. This increases accuracy and zero repeatability during disassembly and reassembly when performing maintenance.

Features and Specifications:
Manufacturer Number: 05-315B
Geissele Automatics AR-15 15" Super Modular Rail MK4 M-LOK Black
Length: 15"
MK4 Inner Diameter: 1.35"
MK4 Outer Diameter: 2.11"
MK4 with Magpul M-LOK attachment system
Picatinny rails sections at 3, 6, and 9 o'clock
Ergonomic
Free Floating
Modular
Installed Weight: 15.4oz
Proprietary 2.25" long barrel nut
Lightweight, Strong and Rigid
Color: Black

Fits:
AR-15 Upper Receivers



Note: MK4 rails are designed to work with Mil-Spec M4 upper receivers. The compatibility with billet receiver sets is unknown.