Pinned and Welded

A pinned and welded muzzle device is a permanently attached muzzle device on an AR-15 barrel, created by drilling a hole through both the device and barrel threads, inserting a hardened steel pin, and then welding over the pin hole. This process makes the muzzle device a permanent part of the barrel assembly.

Why Pin and Weld?

The primary reason to pin and weld a muzzle device is to achieve a legal 16-inch overall barrel length without registering your rifle as an SBR (Short Barreled Rifle). For example, a 14.5-inch barrel with a properly pinned and welded muzzle brake or flash hider of at least 1.5 inches brings the total length to 16 inches, avoiding the need for a tax stamp.

Technical Requirements

The ATF requires that pinned and welded muzzle devices meet specific criteria:

• The weld must be permanent and require cutting or machining to remove
• Silver solder alone is not considered permanent
• The pin typically measures 0.125 inches in diameter
• Penetration depth should be at least 0.050 inches into the barrel

Build Considerations

When planning your build on the AR15 Outfitters builder, consider that a pinned and welded configuration limits future modifications. You cannot easily swap the muzzle device or mount most suppressors without cutting the weld. However, some manufacturers offer suppressor-compatible devices designed for pin and weld applications.

Professional installation typically costs $65-$125, depending on your location and whether you provide the device. Many builders choose this route for 14.5-inch barrel builds to maintain rifle classification while achieving better maneuverability than a standard 16-inch barrel.