The LWRC IC-MKII Oscar Foxtrot 5.56 is a short-barreled piston carbine with a 12.7-inch barrel chambered in 5.56 NATO (LWRCI part no. ICMKIIO5CK12). LWRCI redesigned the IC upper for the MKII with a monoforge one-piece upper receiver and an M-LOK handguard. Its short-stroke gas piston system is built for reliability in harsh conditions, and a two-position adjustable gas block lets you select suppressed or unsuppressed operation. Fully ambidextrous controls and a compact stock keep it easy to handle. It is a good match for shooters who want a compact, piston-driven carbine.

Key Specifications

• The chambering is 5.56 NATO.
• Barrel length is 12.7 inches, a cold hammer forged, Black Nitride treated heavy-profile barrel.
• The twist rate is 1:7 right hand.
• The muzzle is threaded 1/2×28.
• The operating system is a short-stroke gas piston with a two-position A5 gas block.
• The upper is a monoforge one-piece receiver with an M-LOK handguard.
• Controls are fully ambidextrous, including the bolt catch, release, magazine release, safety and charging handle.
• The stock is the LWRCI compact stock, with an Ultra Combat Grip.
• The sights are LWRCI Skirmish back-up iron sights.
• A Magpul 5.56 PMAG 30 magazine is included.

Frequently Asked Questions

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.

Is it a piston or direct impingement rifle? It uses LWRCI’s short-stroke gas piston system.

What magazine does it come with? LWRCI lists a Magpul 5.56 PMAG 30 with the IC MKII.

Buy the LWRC IC-MKII Oscar Foxtrot 5.56 NATO SBR, 12.7-Inch Barrel

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 LWRC‘s AR rifles lineup and our Lubbock, Texas team will handle the transfer.