What is the locking system of the M500 shotgun?

What is the locking system of the M500 shotgun?

• A. Sliding block
• B. Rotating bolt
• C. Lever lock
• D. Gas piston

Answer: (A)

The locking system describes how the breech stays closed when a round fires and then reopens for the next round. In the Mossberg 500, the bolt moves straight back and forth in the receiver, and it has locking lugs that engage with recesses in the barrel extension when the bolt is forward. That forward engagement securely locks the barrel to the receiver, creating a tight, reliable breech. When you cycle the pump, the bolt slides rearward, the lugs disengage to unlock, and the spent shell is ejected. As the forend moves forward again, the bolt slides into the forward position and the lugs re-engage, locking the breech once more. This sliding-block arrangement is simple and robust, which is ideal for a pump-action shotgun that must perform reliably under dirt, mud, and heavy use. It isn’t a rotating-bolt system, a lever-lock, or a gas-piston design—those mechanisms belong to different kinds of firearms.

The locking system describes how the breech stays closed when a round fires and then reopens for the next round. In the Mossberg 500, the bolt moves straight back and forth in the receiver, and it has locking lugs that engage with recesses in the barrel extension when the bolt is forward. That forward engagement securely locks the barrel to the receiver, creating a tight, reliable breech. When you cycle the pump, the bolt slides rearward, the lugs disengage to unlock, and the spent shell is ejected. As the forend moves forward again, the bolt slides into the forward position and the lugs re-engage, locking the breech once more.

This sliding-block arrangement is simple and robust, which is ideal for a pump-action shotgun that must perform reliably under dirt, mud, and heavy use. It isn’t a rotating-bolt system, a lever-lock, or a gas-piston design—those mechanisms belong to different kinds of firearms.