M4-EXO2 Upper Half Customizable Pick your Barrel Length

MSRP: $599.00
Now: $183.99
(You save $415.01 )
(8 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


8 Reviews

  • 5
    Good upper assembly

    Published by Max M on Mar 20th 2020

    Very nice flat top upper receiver assembly. Upper fits tight with the angry patriot lower, no wiggling or jiggling. Rail feels good in the hand, I have medium sized hands and it's a perfect fit, not too wide, not too slim. Does get hot when really blasting away magdumping repeatedly. Gloves are enough to keep the heat from hitting your hand. Paid for the gas block to be staked, well worth it imo. One minor discrepancy is that the rail is a slightly different black than the upper and lower receiver. Could be from a machining finish, could be different anodizers, I don't care enough to complain, it goes bang and that's all that matters.

  • 5

    Published by Michael Harlick on Mar 8th 2020

    I love this upper! SOLGW has some great people working for them and they make superb products. I was planning to have to pin and weld my muzzle device but they did it for me which saved $150. If you are questioning whether or not to buy one, DO IT, you will never need another and the customer service is awesome!

  • 5
    11.5 upper

    Published by Jason Boyd on Feb 28th 2020

    Ordered this upper to pair with my angry patriot lower and the fit and quality are amazing.

  • 5
    Great upper

    Published by Alex Fung on Feb 24th 2020

    Quality upper mated well with my lower no movement

  • 5

    Published by Brady Sprayberry on Feb 8th 2020

    I ordered the 11.5 inch upper on Black Friday of 2019. Received it in the ETA window. Couldn’t ask for me. Best upper I own hands down. Paired it with a rebellious stripes lower. First upper I’ve ordered from sons but it definitely won’t be the last. Don’t hesitate.

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