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Carbon Fibre 12g Shotgun Magazine Extension Tubes


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  • Extremely Light Weight – 73g for a 500mm (+8rd) tube

  • High Strength Carbon Fibre

  • Impact-Resistant Polymer

These carbon 12g shotgun magazine extensions are designed to shed weight from the place it affects you the most – the front of the gun. Enjoy faster transitions and easier gun manipulation by lowering the moving mass. Just 73g on a 500mm tube.

Note: The extension tube will add to the internal standard capacity of the gun; for instance, a Benelli M2 has an internal capacity of 4 rounds, and a +6 extension tube will give 10 rounds total in the magazine tube.

High spec carbon fibre made to our specification with a premium matte finish. The one piece carbon magazine is bonded using cutting edge adhesives used in the automotive industry for sports car chassis.

To calculate the number of rounds, count 60mm per round and +60mm for the spring and follower. For example, for a +8rd tube, you need 8 x 60mm (480mm) plus 60mm which is 540mm. Cut tolerance is +/- 2mm. If you want to increase ammo capacity, especially if you’re shooting modified, choose the external end cap which will gain you 30mm internal capacity for the same length compared to an internal end cap.

For reference, a Beretta 1301 has a standard internal capacity (without an extension tube) of 5, and the Benelli M2 (all variants) has a standard internal capacity of 4. The total capacity of the gun would be the standard internal capacity plus the extension’s capacity. For example, if you would like your Beretta 1301 to have a total capacity of 10 you would need a +5 tube. All known standard internal capacities are listed below.

  • Benelli M2 (all variants) – 4 rounds
  • Benelli Nova SPEED – 5 rounds
  • Benelli Supernova – 5 rounds
  • Beretta 1301 – 5 rounds
  • Breda B12i – 4 rounds
  • Mossberg 940/930 – 4 rounds
  • Stoeger M3000 / M3K – 5 rounds

For any help or recommendations please don’t hesitate to get in touch using the Contact Us form.

Magazine spring is sold separately here.

NOTE: 2-3 weeks for delivery, each tube is made to order! Please read the specifications above. As these are custom tubes, we will not be able to accept returns.