9mm Micro ARP Pistols, AR-9 Uppers & Kits

9mm Micro ARP Pistols, AR-9 Uppers & Kits

A 9mm Micro ARP is a very short AR-9 pistol, a pistol-caliber AR with a 3" to 5.5" barrel. 9mm gives low recoil, low cost per round and easy-to-find ammo. Moriarti Armaments builds 9mm Micro ARP pistols, AR-9 uppers and kits in Miami.

What we offer in 9mm

• Complete pistols: MA-9 Micro ARP pistols with 3", 4.5" and 5.5" barrels, including Classic, FDE and suppressor-ready models.
• AR-9 uppers: slick side, Diamond Cut, Spitfire and M-LOK uppers, many with BCG and charging handle included.
• Kits: 4.5" and 5.5" AR-9 pistol parts kits, including Glock-style kits.

9mm Micro ARP FAQ

What magazines does a 9mm Micro ARP use?

Our MA-9 builds are Glock-style and take Glock-pattern 9mm magazines. Always confirm the magazine type on each product page.

What do LRBHO and non-LRBHO mean?

LRBHO means "last round bolt hold open": the bolt locks back after the last shot. Non-LRBHO uppers do not lock back on an empty magazine. Match the upper to your lower receiver.

Can I put a 9mm upper on a standard AR-15 lower?

Usually not without changes. AR-9 uppers are blowback operated and need a 9mm lower or magazine adapter, a 9mm buffer and a matching magazine.

Is 9mm or 300 Blackout better for a Micro ARP?

9mm is cheaper and softer shooting. 300 Blackout hits much harder from short barrels. See the full Micro ARP collection to compare.