Moriarti AR-45 16" Side Charging LRBHO Upper Assembly with BCG – .45 ACP

AR-45 16" Upper: Specs

The Moriarti AR-45 16" Side Charging Complete Upper Assembly delivers precision, power, and innovative design in a .45 ACP blowback platform. This upper is built on a non-reciprocating side-charging billet upper receiver with integrated Last Round Bolt Hold Open (LRBHO) for improved functionality and performance.

Whether you're building a pistol-caliber carbine or looking for a reliable .45 ACP AR upgrade, this complete upper—fully assembled and test-fired—is engineered for smooth cycling, modularity, and compatibility with Glock mag AR-style lower receivers.

Key Features:

• Barrel: 16" Match-Grade .45 ACP, 4150 CrMoV steel, black nitride finish, 1:16 twist, threaded 5/8x24 with A2 flash hider

• Upper Receiver: Side-charging, non-reciprocating, billet 6061 aluminum, Mil-Spec anodized, includes LRBHO

• Handguard: Rifle-length (approx. 15") M-LOK free-float, aircraft-grade aluminum, hardcoat anodized

• Gas System: Blowback operation (no gas block required)

• Bolt Carrier Group (BCG):

  • US-made 8620 steel

  • Phosphate finish

  • M16 cut

  • Glock & Colt compatible

• Charging Handle: Side charging, non-reciprocating

• Weight: 4.2 lbs

• Compatibility: Works with Moriarti AR-45 billet lowers and most Glock-mag lowers

• Current Lead Time: Approx. 14–30 days (Made to order)

Note: For optimal performance, Moriarti recommends using a heavy buffer when building your AR-45 with this upper.

• Pair with the Moriarti AR-45 Billet Lower Receiver

FAQ

What lower does it fit?

A dedicated pistol-caliber AR lower that takes Glock-style .45 ACP magazines. A standard AR-15 lower with 5.56 magazines will not feed it.

How does it operate?

It is a direct blowback pistol-caliber design with no gas tube or gas block, so 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 when used with an LRBHO-compatible lower.

What is a non-reciprocating side charger?

The charging handle is on the side of the upper and does not move while firing, so you can charge it without breaking your grip.

Is a lower receiver included?

No. This is an upper assembly only; the lower receiver and magazine are sold separately.

Related: AR-45 upper assemblies · pistol caliber carbines

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