The Magpul MOE SL Mid-Length Handguard (brand part number MAG551-BLK) is a direct replacement for the factory plastic, two-piece mid-length handguard found on most AR15/M4 rifles running an A2 front sight. Reinforced, heat-resistant polymer construction delivers real durability without the weight or expense of an aluminum rail, and an integral riveted aluminum heat shield protects your support hand from barrel heat. M-LOK slots at the 2, 6, and 10 o’clock positions accept Picatinny rail sections and direct-attach accessories, so you can add lights, slings, or grips exactly where you want them. It installs using your rifle’s existing round front retaining cap and delta ring, but it’s not compatible with piston-operated uppers or triangular retaining caps.

Key Specifications

• Sized for mid-length gas systems with an A2 front sight.
• Built from reinforced, heat-resistant polymer for durability without aluminum weight or cost.
• Includes an integral riveted aluminum heat shield.
• M-LOK slots at the 2, 6, and 10 o’clock positions.
• Accepts Picatinny rail sections and direct-attach M-LOK accessories.
• Features a large front extension and lower lip that shields your hand from the hot front sight assembly.
• Installs using the existing delta ring and round front retaining cap.
• Requires a round front retaining cap; triangular caps are not compatible.
• Not compatible with piston-operated AR platforms.
• Made in the USA.

Frequently Asked Questions

Will this work with a piston-operated upper? No, it’s designed for direct impingement systems only, not piston-operated AR platforms.

What front sight does this require? The A2 front sight assembly; other gas blocks are not compatible.

What retaining cap does this need? A round front handguard retaining cap and rear spring-loaded delta ring; triangular retaining caps are not compatible.

Buy the Magpul MOE SL Mid-Length AR Handguard

Magpul built the MOE SL as a lightweight, cost-effective step up from a worn factory two-piece handguard, without the price of a full aluminum rail. Shop more Magpul Industries parts or browse our full AR handguards selection to complete your build. Order it from our Lubbock, Texas gun shop for fast, reliable shipping.