This Carlson’s magazine extension (mfr. part no. 04508) adds 7 rounds of capacity to a 12-gauge Benelli M4 shotgun. It threads on in place of the factory magazine cap and ships with everything needed to install it.

Key Specifications

• Adds 7 rounds to your shotgun’s magazine capacity.
• Chambered for 12-gauge shells.
• Fits the Benelli M4 shotgun.
• Constructed of blued solid steel.
• Includes a spring.
• Includes a base clamp with swivel stud (works with a QD sling swivel, sold separately).
• Includes a high-visibility follower.
• Threaded tube design replaces the factory magazine cap.
• Ships with easy-to-follow installation instructions.
• Manufactured by Carlsons.

Frequently Asked Questions

Does this extension work as a standalone magazine?

No, it’s an add-on tube that threads onto your Benelli M4’s existing magazine tube in place of the factory cap, adding 7 rounds of capacity.

What’s included in the box?

The extension tube, a spring, a base clamp with swivel stud, a high-visibility follower, and installation instructions.

Buy the Carlson’s Benelli M4 Magazine Extension

Shop the Carlsons lineup or browse our full Shotgun Magazines selection to find the right fit for your firearm.