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U.S. Arms M4 UTAW Pro 300 Blackout Rifle

ATF regulated items have restrictions and requirements:

  • Your order will ship only to a Federal Firearms License holder.
  • We are not currently shipping to CA, CT, DC, HI, MD, MA, MN, NJ, NY, or VA.
  • Please be sure to contact your local FFL dealer prior to placing your order to ensure they are still accepting transfers. Some FFL dealers are not open due to Covid-19.
  • Customer must read, understand, and agree to customer terms and conditions.



The U.S. Arms M4 UTAW Pro series rifle takes the already outstanding M4 UTAW and adds some gas to the fire. We always stand behind the principles that our rifles MUST be lightweight, durable, and accurate, and the M4 UTAW Pro series is no exception. This series is offered in 5.56 NATO or .300 Blackout chambering. This rifle can be configured with a black anodize or a multitude of Cerakote options for the handguard, trigger guard and receiver set. This rifle can be specced with our patented “Cam Lock” lower receiver so that you get the tightest receiver fit on the market. The Cam Lock lower receiver will also fit any mil-spec upper assembly. We are proud to claim we are “home of the World’s Tightest Receivers”.  You may also spec this rifle with our standard lower receiver, but with fewer color options.

The M4 UTAW Pro series is available in multiple colors and finishes:

  • Anodized Black
  • Cerakote Black
  • Cerakote Chocolate Brown
  • Cerakote Gun Metal Gray
  • Cerakote Alpine Dark Camo
  • Cerakote Arctic Camo
  • Cerakote Battle-Worn Bronze
  • Cerakote Battle-Worn Titanium
  • Cerakote Bazooka Green
  • Cerakote Woodland Camo

U.S. Arms Company wanted to make upgrades to the already great shooting experience one gets from the M4 UTAW. This consequently and inherently made the M4 UTAW Pro series more accurate and gives the shooter more confidence at the range, on a hunt, in a competition, or for home defense. We made upgrades to the handgrip, trigger, safety selector, back plate, and give the shooter the ability to choose the type of lower receiver and muzzle device that best suits their needs. The barrel installed in this weapon system is constructed from a 4150 chrome moly cold hammer forging. The barrel is then phosphate coated, chrome lined, and equipped with a nickel boron barrel extension. As a result of using a nickel boron extension and the bolt carrier group being a U.S. Arms M16 full auto nickel boron bolt carrier group, allows the shooter to experience extremely smooth cycling. The trigger in this weapon system is a Trigger Tech Duty Trigger. This trigger is second to none in its class, with an extremely short take up, clean crisp break at a a 3.5lb pull, and a very short, positive reset which gives the shooter an overall better shooting experience.  The M4 UTAW Pro series also comes equipped with an ambidextrous Radian Raptor charging Handle, a more ergonomic ERGO grip, and a QD back plate. More details can be found below.


Cam-lock vs. Standard receiver.

Our cam-lock receiver reduces unwanted movement and improves stability. This patented design significantly enhances the precision and consistency of your shots. Whether you’re engaging targets at the range or participating in competitive shooting events, the addition of cam-lock empowers you to achieve unparalleled accuracy.

Additionally, our cam-lock lower is designed to be compatible with a wide range of AR-15 uppers , making it a versatile upgrade option for your rifle.


U.S. Arms Company considered  the M4 UTAW Pro series and decided on many upgrades and configurability options from its little brother, the M4 UTAW. These upgrades are subtle yet significant, allowing the shooter to have better shooting experience, more tools to be as accurate as possible, and of course confidence for home defense and sport shooting . The M4 UTAW Pro series rifle is the next level of perfection from U.S. Arms Company.


Note: Cerakote items may require up to 2 weeks processing time.



.300 AAC Blackout

Muzzle Thread

5 / 8 × 24 threads per inch

Mounting System

Picatinny top rail and M-LOK slots


6.85 lbs


35.5" – 39.4"


Two 30-round Lancer L5-AWM Black

Barrel Length


Barrel Profile


Gas System

Carbine Length

Product Benefits

  • Designed and engineered to allow significant weight reduction without sacrificing strength
  • Machined to aerospace tolerances in a ISO certified aerospace facility

Details and Build Materials

  • Receiver Set: 7075-T6 aluminum mated set by U.S. Arms Company
  • Trigger: Trigger Tech Single Stage 3.5lb Drop in Trigger
  • Safety: TrigerTech Ambidextrous AR Safety 45-90
  • Hand Grip: ERGO Grips Flat Top Tactical SUREGRIP (If equipped with our standard lower receiver, the grip will have a beaver tail)
  • Buffer Assembly: Mil-Spec 6 position aluminum buffer tube with H1 buffer and Sprinco reduced power buffer spring
  • Back Plate: QD Steel back plate
  • Buttstock: Magpul CTR Mil-Spec Stock
  • Bolt Carrier Group:U.S. Arms Nickel boron M16/4 full-auto, MP tested, with properly staked gas key
  • Charge Handle: Radian Raptor Ambidextrous
  • Handguard: 15″ aluminum free-floating with full-length top Picatinny rail, side and bottom M-LOK slots, and side QD mount points
  • Sights: None
  • Barrel: Cold Hammer Forged 4150 chrome moly, 6 groove, 1:7 twist, with chrome lining, manganese phosphate coating, and a nickel boron extension
  • Gas System: Mil-spec phosphate coated .750″ gas block and stainless carbine-length gas tube
  • Muzzle Device: Strike Industries Venom flash hider
  • Magazine: 2 Lancer Systems L5AWM 30 round magazines
  • Case: SKB iSeries 4909-5 single rifle case