Geissele Mk4 Federal 10" ODG Rail for FBI build

ships from our shop in 3 to 5 days (+/-)

Geissele Mk4 Federal 10" ODG Rail M-LOK

Mod 2 with longer lower rail for Federal Law Enforcement

The OD Green Mk4 10" rail is known for its federal law enforcement use, especially the FBI.  The FBI HRT build is made possible with this highly sought after rail for FBI rifle clone building.

The Super Modular Rail (SMR) Mk4 M-LOK™ is a Geissele classic.  While one the first SMR rails, it remains one of the most popular for AR pistols and short barreled rifles and PDW builds.

This is the same rail used to fulfill contracts for the Federal Bureau of Investigation (FBI). It’s strength, modularity and M-Lok compatibility gives users the capabilities needed to successfully complete the mission at hand.

These rails are purpose-built and feature integrated M1913 picatinny rail sections at the fore of the rail in the 3, 6 and 9 o’clock positions. The Picatinny rail on the bottom of the rail, or the 6 o’clock position, is elongated in this version to more comfortably accommodate accessories. Maximum venting for heat dissipation also dramatically reduces the rails overall weight, while maintaining its same strong and rigid platform. The MK4 M-LOK rail features M-LOK slots at the 3, 6 and 9 o’clock positions as well as the upper 45° quadrants. This allows the user to keep the weight on the rail system down, while keeping the modularity and versatility to attach accessories as necessary.

Note: package contains rail, barrel nut and allen wrenches.  Does not contain gas block. Does not contain barrel nut wrench

Manufacturer's Product No.  05-430ODG

MK4 Height:




MK4 ID*:


MK4 OD*/DAQ*:                 


Installed Weight
(w/ Hardware):

10" Mk4 Rail - 11.8oz

ID* - Inner Diameter
OD* - Outer Diameter
DAQ* - Distance Across Quadrants

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