Andro Corp ACI-15 Halo 5.56 10.3 in Pistol – Proven SBA3 Build

Description

The Andro Corp ACI-15 Halo 5.56 10.3 inch AR pistol is Andro Corp’s answer to the question of how short you can go in 5.56 NATO before the cartridge stops working. Ten and three tenths inches is the practical floor: long enough to keep useful velocity and a reliable gas curve, short enough that the whole gun handles like a submachine gun. Andro Corp Industries builds it in the USA under part number 556103HB, UPC 796258933312, and MAG5 Firearms has it in stock.

Why 10.3 inches is the number on the Andro Corp ACI-15 Halo 5.56 10.3

Barrel length in 5.56 NATO is a straight trade between muzzle velocity and handling, and it is not a linear one. Drop below about ten inches and you start losing velocity fast while gaining muzzle blast you will notice indoors. At 10.3 inches the round still leaves fast enough to do its job at realistic distances, and the gun is genuinely short.

The barrel is 4150 chrome moly vanadium steel with a QPQ nitride finish inside and out, cut 1:7. That twist stabilizes everything from 55 grain up through the 77 grain match loads people use in short barrels, and the muzzle is threaded 1/2-28 under an A2 flash hider.

The Andro Corp ACI-15 Halo 5.56 10.3 inch pistol runs a carbine length gas system behind a .750 low profile gas block. On a 10.3 inch 5.56 barrel that is the correct length, and it is why this gun cycles without the buffer weight experiments a shorter gas system would demand.

Receivers, handguard and the brace

The upper on the Andro Corp ACI-15 Halo 5.56 10.3 inch is 7075-T6 forged with T-markings, a forward assist and an ejection port cover, running an M16 profile nitride bolt carrier group. The lower is 7075 forged with a type 3 hard coat anodized finish and a mil-spec parts kit, so every aftermarket trigger, safety and grip you already own drops in.

Out front the Andro Corp ACI-15 Halo 5.56 10.3 inch carries a 9 inch M-LOK free float handguard. It clears the gas block and leaves you a useful stretch of rail for a light and a hand stop without turning a compact gun into a heavy one.

The Andro Corp ACI-15 Halo 5.56 10.3 inch pistol ships with an SB Tactical SBA3 adjustable stabilizing brace on a carbine receiver extension, which is what keeps it classified as a pistol. Fitting a conventional shoulder stock to a barrel this short creates a short barreled rifle, which requires ATF approval and a tax stamp first. MAG5 Firearms does not sell NFA items.

Andro Corp ACI-15 Halo 5.56 10.3 inch specifications

• Caliber: 5.56 NATO
• Barrel: 10.3 in, 4150 CMV steel, QPQ nitride finish
• Twist rate: 1:7
• Muzzle: 1/2-28 threads with A2 flash hider
• Gas system: carbine length with .750 low profile gas block
• Upper receiver: 7075-T6 forged, T-markings, forward assist, ejection port cover
• Lower receiver: 7075 forged, type 3 hard coat anodized
• Bolt carrier group: M16 profile, nitride finish
• Handguard: 9 in M-LOK free float
• Brace: SB Tactical SBA3 adjustable stabilizing brace
• Grip: A2
• Capacity: 30+1, one magazine included
• Part number: 556103HB
• UPC: 796258933312

Andro Corp Industries covers the ACI-15 line with a lifetime warranty and publishes the full build sheet on the Andro Corp Industries product page, and SB Tactical documents the adjustment range of the SBA3 fitted here. Quote part number 556103HB when you order, because the same Halo is also sold with the minimalist MPS stabilizer and in 300 Blackout. If the bigger cartridge is what you want, the ACI-15 Halo in 300 Blackout is the same gun rebarreled, and the rest of our in stock firearms are worth a look.

A carbine length gas system means it runs reliably without buffer tuning, which is not true of every short 5.56 build.

The 1:7 twist handles heavy 77 grain loads, which matter more out of a short barrel than a long one.

The SBA3 adjusts across five positions, so it fits over a jacket or a plate carrier without tools.

Forged mil-spec receivers mean your existing AR-15 parts, magazines and optics all carry straight over.

Anyone who wants a compact 5.56 for a truck, a pack or a bedside safe, and anyone building toward a suppressed setup once the ATF approves the stamp, which is a separate purchase. If you already own a 16 inch carbine and want something meaningfully handier rather than a duplicate, the Andro Corp ACI-15 Halo 5.56 10.3 inch pistol is the obvious next step.