AR-10MM 5" Slick Side Complete Upper – LRBHO, Micro ARP

10mm Micro Upper: Specs & Features

Experience the power of 10mm Auto in an ultra-compact package with the Moriarti AR-10MM 5" Slick Side Complete Upper. Engineered for Micro ARP and AR pistol builds, this complete upper combines premium American-made components with reliable blowback operation for exceptional performance in a lightweight platform.

Built around a 5-inch match-grade barrel, billet slick-side receiver, and Last Round Bolt Hold Open (LRBHO) system, this upper is designed for shooters seeking a compact, dependable solution for recreational shooting, range use, and custom AR builds. Compatible with Glock-pattern magazine lowers, it includes a ramped bolt carrier group, charging handle, and a 4-inch free-float M-LOK handguard, providing everything needed to complete your upper assembly.

Whether you're building a Micro ARP, 10mm AR pistol, or a compact backpack firearm where lawful, this upper delivers the durability, reliability, and performance expected from Moriarti Armaments.

Features

• Caliber: 10MM Auto
• Barrel: 5" Match Grade
• Barrel Material: 4150 Chrome Moly Steel
• Finish: Black Nitride
• Twist Rate: 1:16
• Thread Pitch: 5/8x32
• Muzzle Device: A2 Flash Hider
• Operating System: Blowback
• Upper Receiver: Slick Side 6061 Billet Aluminum
• Finish: Type III Hardcoat Anodized
• Last Round Bolt Hold Open (LRBHO)
• No Forward Assist
• No Dust Cover
• Handguard: 4" Free-Float Slim M-LOK
• Bolt Carrier Group: Ramped, 8620 Steel, Glock & Colt Compatible
• Charging Handle: Mil-Spec
• Compatibility: Glock-Mag AR-9 / AR-40 / AR-45 Pattern Lowers
• Approximate Weight: 3.2 lbs
• Made in USA

Why choose a 10MM AR pistol?

A 10MM AR pistol delivers significantly more energy than traditional pistol calibers while maintaining the modularity and familiar controls of the AR platform. Its combination of increased power, flat trajectory, and compatibility with Glock-pattern magazines has made it a popular choice for enthusiasts building compact AR platforms.

Images may not be the exact representation of the product.

FAQ

Is a lower receiver included?

No. This is an upper assembly only; the lower receiver, magazine and sights are not included.

What lower does it fit?

A dedicated pistol-caliber AR lower, such as a Glock-pattern lower using 10mm Glock-style magazines. A standard AR-15 lower with 5.56 magazines will not feed it.

How does it operate?

It is a direct blowback system, so it has no gas tube. A heavy PCC buffer is used for reliable cycling.

Does it have last round bolt hold open?

Yes. It has LRBHO, so the bolt locks back after the last round.

Related: 10mm Micro ARP · all Micro ARP pistols and uppers