The Colt M5 Carbine 10.3-inch SBR is Colt’s M5 Carbine with a 10.3-inch barrel in 5.56 NATO, the semi-automatic version of the rifle Colt builds as the next evolution of its M16 and M4 platforms (Colt part no. CM556-10H-M5S). Colt redesigned both receivers for the M5, with fully ambidextrous controls and an upper receiver whose true free-float barrel system isolates the barrel from external pressure. The 7-sided Magpul M-LOK handguard carries an uninterrupted MIL-STD-1913 top rail, and a keyed anti-rotation tab keeps it from shifting at the receiver. Flip-up front and rear sights and a Radian Raptor ambidextrous charging handle are fitted, and the rifle ships with one 30-round magazine. It keeps compatibility with many M4 components, so parts and training carry over.

Key Specifications

• The chambering is 5.56 NATO, the cartridge the M4 and M5 family are built around.
• Barrel length is 10.3 inches, with a chrome-lined Cr-Mo-V steel barrel that Colt HP and MPI tests.
• Rifling twist is 1:7, which stabilizes heavy and long-for-caliber 5.56 bullets.
• Capacity is 30+1, and one 30-round magazine is included.
• Controls are fully ambidextrous, including the selector, magazine catch and bolt catch and release.
• The barrel is true free floating, isolated by the upper receiver design for repeatable accuracy.
• The handguard is a 7-sided Magpul M-LOK design with an uninterrupted MIL-STD-1913 top rail.
• The charging handle is a Radian Raptor ambidextrous unit that works even with a large optic mounted low.
• Sights are flip-up front and rear, ready as primary irons or backups under an optic.
• The lower receiver is forged 7075-T6 aluminum, a high strength-to-weight material.

Frequently Asked Questions

Which M5 barrel length is the shortest? The 10.3-inch model is the shortest semi-automatic M5 carbine Colt lists, alongside 11.5-inch and 14.5-inch versions.

Do I need ATF approval to buy this? No. As of October 9, 2026, ATF no longer requires Form 4 approval, registration or a tax stamp for short-barreled rifles. It transfers on a Form 4473 with a background check through a Class 3 (SOT) dealer. State and local laws still apply. Taking an SBR across state lines still requires an approved ATF Form 5320.20.

How does the M5 differ from an M4-pattern carbine? The M5 adds fully ambidextrous controls, a free-float barrel system with a self-centering barrel nut and keyed barrel extension, and a 7-sided M-LOK handguard, while keeping compatibility with many M4 components.

Buy the Colt M5 Carbine SBR, 10.3-Inch

As of October 9, 2026, this short-barreled rifle transfers on a Form 4473 with a background check at your Class 3 (SOT) dealer, with no Form 4 or tax stamp; state and local laws still apply. Order through Colt‘s short-barreled rifles lineup and our Lubbock, Texas team will handle the transfer.