The LWRC ICMKII SBR in 5.56 NATO with a 12.7-inch barrel is a short-barreled rifle from LWRCI’s redesigned Individual Carbine line (LWRC part no. ICMKIIR5B12S). The updated upper receiver accepts an M-LOK handguard, and the two-position adjustable gas block now sits inside the rail where it is easy to reach. It runs LWRCI’s patented short-stroke gas piston, which keeps the action cleaner and simpler to maintain than a direct-impingement design. The rifle is black anodized and ships with a Magpul 5.56 PMAG 30. A 12.7-inch barrel splits the difference between the shortest and longest ICMKII options for shooters who want some extra velocity from a compact rifle.

Key Specifications

• The chambering is 5.56 NATO, a widely available cartridge for training and duty use.
• Barrel length is 12.7 inches, one of the four barrel lengths offered in the ICMKII line.
• Rifling is a 1:7 right-hand twist in a cold hammer forged, Black Nitride treated heavy-profile barrel, which stabilizes a wide range of bullet types.
• The operating system is LWRCI’s short-stroke gas piston, which resists fouling and keeps maintenance simple.
• The A5 two-position gas block sits inside the rail and selects suppressed or unsuppressed settings.
• The upper is a Monoforge one-piece forging with an integrated rail base, stronger than a standard-pattern upper.
• The muzzle is threaded 1/2×28 TPI, ready for common 5.56 muzzle devices.

Frequently Asked Questions

What color is this ICMKII? This rifle is black anodized. LWRCI also offers the ICMKII in flat dark earth, patriot brown, tungsten grey and OD green.

Are the controls ambidextrous? Yes. LWRCI builds the ICMKII with fully ambidextrous controls, including the bolt catch, bolt release, magazine release, safety selector and charging handle.

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.

Buy the LWRC ICMKII 12.7-Inch SBR, 5.56 NATO, Black

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. The piston operating system and M-LOK rail make this a low-maintenance compact rifle for suppressed or unsuppressed use. Order through LWRC‘s short-barreled rifles lineup and our Lubbock, Texas team will handle the transfer.