M4-EXO2 Upper Half Customizable Pick your Barrel Length

MSRP: $599.00
Now: $152.99
(You save $446.01 )
(3 reviews) Write a Review
Custom Uppers ship in 2-6 weeks.



The M4-EXO2 is our newest entry level upper packed with great features.  The Sons of Liberty EXO2 MLOK rail is the best on the market at its price point, it looks great and locks up rock solid.  Built with the same high quality components that have given us our reputation for guns that never stop running, you can't beat it at this price.

Barrel: Sons of Liberty Gun Works 16” 4150CoMOV 1:7 MPI HPT Barrel
Caliber: 5.56 NATO Chamber
Barrel Steel: 4150 CrMoV (Chrome Moly Vanadium per MIL-B-11595E)
Twist Rate: 1/7 Twist Six Groove
Thread Pitch: 1/2-28 Threaded Muzzle
Gas Block: .750″ Gas Block Journal with appropriately sized gas port
Weight: 27 Ounces
Barrel Finish: QPQ Corrosion Resistant Finish
Barrel Extension: QPQ coated M4 Feed Ramp Extension
High Pressure (proof) Tested (HPT)
Magnetic Particle Inspected (MPI)

Upper Receiver:
Material: Made from Mil-Spec 7075-T6 aluminum Cerra Forge forgings.
Exterior Finish: Anodized to Mil-Spec MIL-A-8625F, Type III, Class 2, Hard Anodic Coating, Flat Black Dye, Non-Reflective, NiAc Seal
Interior Finish: Dry Film Lube
T-Marks: Engraved T-Marks

Gas Block: Sons of Liberty Lo-Pro Gas block made from 4140 Steel and Nitride Treated

Gas Tube: Sons of Liberty Melonited Stainless Steel


Weight: 12.9oz in 15"

MLOK Slots at 3,6,9 O'Clock

Continuous top rail at 12 OClock

Muzzle Device: Mil-Spec A2 Flash Hider

Sights: Front and Rear ARMS #71L Flip Up Polymer Sights

Additional Details


3 Reviews

  • 5
    Fantastic product

    Published by Taylor Ward on Sep 29th 2019

    Absolutely love this upper. Wouldn’t go a different rout ever!

  • 4

    Published by Brian Vickery on May 5th 2019

    Was eagerly awaiting the upper, and it did not disappoint. One thing to be aware of is the tolerances of the uppers are really tight. Right now rear take down pin is tight on my lower (Anvil Arms)., so ordered a SOLGW stripped lower to make a new SBR.

  • 5
    M4-EXO2 Upper

    Published by Campbell Homer on Apr 26th 2019

    When I ordered this upper, I kept the options mostly stock, although I opted for the 1/8 twist .223 Wylde barrel, and I couldn't be any more impressed. The upper is handy and fairly light, shoots great groups (even with cheaper ammo like American Eagle and Wolf Gold), and overall the fit and finish is on par with other brands like BCM, with not a single rough mark in sight. The price point makes it a steal, especially with my tight budget, and I certainly recommend this to anyone looking for a genuinely good upper.

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