LMT Rear Sight Assembly for Mk18 CQBR Mod0

The LMT L8A rear sight assembly — the original program-correct rear iron sight for the Mk18 Mod 0 CQBR, 100% factory LMT production.

• Clone-correct for Mk18 Mod 0: the LMT L8A is the rear sight specified on the original CQBR upper, first deployed in 2001
• A2-based design, removable: heavy-duty construction based on the M16A2 rear sight, adapted for flat-top Picatinny mounting
• Co-witnesses with "F" height front sights: designed to pair with standard front sight base and red dot optics
• Adjustable for windage and range: dual-aperture with elevation drum for range adjustment

The LMT L8A rear sight has a specific place in the Mk18 lineage. When the US Navy developed the Mk18 Mod 0 CQBR in 2001 as a shortened upper for shipboard defense and close-quarters operations, the L8A was the specified rear iron sight. The design is based on the proven M16A2 rear sight — same dual-aperture flip, same elevation drum — but adapted for removable mounting on a flat-top Picatinny rail. The heavy-duty construction is deliberate: the original Mk18 Mod 0 was a combat tool for NSW SEAL teams operating in maritime environments where corrosion and impact were constant concerns.

The L8A co-witnesses with "F" height front sight posts and is designed to work alongside red dot optics — the standard Mk18 Mod 0 configuration ran the L8A as a backup behind an Aimpoint or EOTech. The sight mounts to the rear of a flat-top upper via a standard Picatinny clamp and can be removed to clear the rail for magnified optics or other accessories.

This is a 100% factory LMT product — not a reproduction, not a third-party copy. For Mk18 Mod 0 clone builders, the L8A is one of the defining components that separates a correct build from a parts-bin approximation.

We stock these for the Mk18 community. If you're building a Mod 0, this is the rear sight. We've got your six on the clone-correct details — add to cart and build it right.