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Sons of Liberty Gun Works M4-76 5.56 AR-15 Rifle - 13.7"

AR-15 Rifle

Out of stock

FFL Required Before Shipping.

Please have your dealer email a copy of their FFL to [email protected] or fax it to 253-218-2998, referencing your name and order number.


At Sons of Liberty Gun Works they believe in Quality Mil-Spec or better parts. They believe there is no substitute for quality and that your gun should be built right the first time, ready for hard use right out of the box. They believe a quality Bolt Carrier Group and a quality, accurate and long lasting barrel are the heart of a Combat Grade weapon. They believe in properly tuned weapons using the correct gas system length and quality buffer system components such as the Vltor A5 system and Sprinco Tactical Buffer Springs. They believe in their products and they back them up with a Lifetime Warranty. Their weapons their meant to be used hard and go in harm’s way, they won’t let you down.

All rifles are test fired twice in shop to ensure proper function.

The M4-76 is their premier fighting rifle, featuring a 13.7″ combat grade barrel, A5 buffer system, Liberty Fighting Trigger, and B5 furniture. At Sons of Liberty Gun Works they always tell their customers, its not what a rifle company tells you, it’s what they don’t tell you. Below you will find the complete specifications on the M4-76. They have built their guns to run through years of hard use, and they have nothing to hide.


  • Barrel: Sons of Liberty Gun Works 13.7” 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
  • Barrel Finish: QPQ Corrosion Resistant Finish
  • Barrel Extension: QPQ coated M4 Feed Ramp Extension
  • High Pressure (proof) Tested (HPT)
  • Magnetic Particle Inspected (MPI)

Lower Receiver:

  • Lower Receiver: Sons of Liberty Gun Works Forged Lower Receiver – Angry Patriot
  • Material: Made from Mil-Spec 7075-T6 aluminum Cerra Forge forgings
  • Finish: Anodized to Mil-Spec MIL-A-8625F, Type III, Class 2, Hard Anodic Coating, Flat Black Dye, Non-Reflective, NiAc Seal
  • Contour is fully machined leaving no flash marks from the forging.
  • Hidden lowers are cut with M16 auto pocket.
  • Safe, Fire, and Full Auto Pictograms.
  • Various Roll Marks
  • Fire Control Group: Liberty Fighting Trigger 6- 6.5lb
  • Safety Selector: Sons of Liberty Gun Works Ambi Selector
  • Grip: B5 P23 Grip
  • Stock: B5 Bravo Stock Black
  • Buffer System: Enhanced A5 Buffer System
  • Receiver Extension: 9 Position Loyal 9 Receiver Extension Tube made from 7075-T6 Aluminum
  • Buffer: A5H2 Buffer
  • Buffer Spring: Sprinco Green Spring
  • Receiver End Plate: Quick Detach End Plate with properly staked Forwards Controls Design Castle Nut

Upper Receiver:

  • Material: Made from Mil-Spec 7075-T6 aluminum Cerra Forge forgings.
  • Finish: Anodized to Mil-Spec MIL-A-8625F, Type III, Class 2, Hard Anodic Coating, Flat Black Dye, Non-Reflective, NiAc Seal
  • T-Marks: Engraved T-Marks
  • Charging Handle: SOLGW Liberty Ambi Charging Handle
  • Gas Block: Sons of Liberty Lo-Pro Gas block made from 4140 Steel and Nitride Treated with Knurled Head Set Screws
  • Gas Tube: Sons of Liberty Mid Length Melonited Stainless Steel
  • Rail System: 13″ Sons of Liberty Gun Works M76 Wedge Lock Rail system.
  • Inside Diameter: 1.3″ ID
  • Finish: Mil-Spec Type III Class 2 Hard Coat Anodizing per Mil-Spec Mil-Spec MIL-A-8625F
  • Barrel Nut: Steel with QPQ Finish
  • Free Floating Design
  • Grade 8 Fasteners
  • Anti Rotation- Anti Slip Design
  • No Special Tools Need for Barrel Nut
  • Continuous top rail design
  • Mil-Spec 1913 Mounting rails
  • Muzzle Device: Sons of Liberty Gun Works NOX9
  • Sights: None, Optics Ready

Includes: Tactical Soft Case, Three SOLGW Steel 30rd Mags, 2oz Bottle of S.P.E.C. 76 Lubricant, SOLGW Sticker & Patch, copy of the US Constitution, and LIFETIME Warranty Certificate

More Information
SKU M4-76-13.7
Product Type AR-15 Rifle
Manufacturer Sons of Liberty Gun Works
Gas Block Diameter .750"
Thread Pitch 1/2x28
Twist Rate 1:7
Color Black
Gas Length Mid
Rail Length 13"
Platform AR-15
Barrel Length 13.7"
Caliber 5.56 NATO
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