Benelli M4 Extension Tube

Benelli M4 Magazine Extension Tube options:

• 7rd – Titanium in Black (Black Cerakote)
• 7rd – Titanium in H2O (Titanium Cerakote)

• 2rd – Steel in Black (Black Oxide)
• 2rd – Steel in H2O (Titanium Cerakote)

Coming soon (subscribe to emails to be notified):

• 7rd 922(r) – Steel in Black (Black Oxide)
• 7rd 922(r) – Steel in H2O (Titanium Cerakote)

• 2rd – Titanium in Black (Black Oxide)
• 2rd – Titanium in H2O (Titanium Cerakote)

Benelli M4 Extension Tube Overview:

The Benelli M4 Extension Tube increases capacity by 2 rounds making your shotgun 7+1 capacity. The 2rd extension tube replaces the Benelli OEM aluminum limiter that comes installed on civilian model M4s. The full 7rd extension tube completely replaces the Benelli M4 OEM 5rd tube and aluminum limiter.

All extension tube options on this page perform the same function; they increase the capacity of your shotgun by 2 rounds. However, the full 7rd extension tubes are lighter weight (compared to the 2rd extension and OEM 5rd tube) and looks better on your shotgun (in most people’s opinion).

None of these extension tubes ship to MA or NJ (if you have a friend in a different state, ship it to their house and use it when you travel to their state).

Benelli M4 Extension Tube Colors:

• Black on the Steel Extension Tubes: Is a black oxide coating that closely matches the dark grey phosphate barrels on the Benelli M4/ M1014.
• Black on Titanium Extension Tubes: Is a black Cerakote coating that closely matches the dark grey phosphate barrels Benelli M4’s/ M1014’s.
• H2O on Steel or Titanium Extension Tubes: Is a Titanium Cerakote coating that almost perfectly matches the Benelli M4 H2O (Titanium Cerakote) coating.

Note: Extension tubes may not match perfectly because Benelli’s coatings can vary slightly, and our coatings can vary slightly. Our extension tubes are not guaranteed to match clones.

Benelli M4 Extension Tube 2rd – Steel:

Made from solid, cold rolled steel bar. This process gives it better grain structure and increased strength. This steel bar is precision machined, inside and out, into the finished product. It is nearly an exact match of the Benelli M4 OEM extension tube. This part is 100% made in America, but doesn’t replace the entire assembly (5-round tube and limiter) as our 7rd extension tube 922(r) does, so it doesn’t count as a 922(r) part (unless paired with an American made 5rd tube).

• Length: 6.5”
• Weight: 3.3oz

Clone Compatibility: This extension tube is made specifically for the Benelli M4 and is not guaranteed to fit any clones. However, according to customer feedback, here is the list of clone's fitments (fitment has not been 100% confirmed):
 
- Panzer M4 – NO
- Black Aces S4 Pro – YES
- MAC 1014 – YES
- Aska M4 – YES
- SDS Tac12 – YES
- SDS S4 – NO
- Sulun Tac12 – YES

Other measurements to test for clone compatibility: It adds 4.5” of length to the 5rd tube. Threads have 2mm thread pitch on external and internal threads (5 threads per cm). It has a 1” Major diameter (diameter of tube where threaded).

Benelli M4 Full Extension Tube 7rd – Titanium:

Crafted from ultra-strong, ultra-lightweight titanium. Our titanium extension tubes are nearly half the weight as our steel tubes, and they are higher strength. Titanium also has the added benefit of being virtually rust and corrosion-proof, even in salt water. Our titanium extended tubes are precision CNC machined, assembled, and Cerakoted in the USA. The titanium extended tube weighs in at just under 50% of the weight of the OEM 5rd tube and 2rd limiter, in part because they are permanently bonded with an aluminum ring to further reduce weight. It is made partially from imported materials. 

• Length: 18.25”
• Weight: 4.9oz

Clone Compatibility: This extension tube is made specifically for the Benelli M4 and is not guaranteed to fit any clones. However, according to customer feedback, here is the list of clone's fitments (fitment has not been 100% confirmed):
 
- Panzer M4 – NO

Measurements to test Clone Compatibility: 18.25” in total length. Length that sticks out of the receiver when it is installed is 17.5”. Length that screws into the receiver is about 0.75”. Threads have 2mm thread pitch (5 threads per cm). It has a 1” Major diameter (diameter of tube where threaded).

Benelli M4 Full Extension Tube 7rd 922(r) – Steel:

Crafted from high-quality precision machined chromoly steel. Chromoly steel is superior to many other steel alloys due to its high strength-to-weight ratio, and its resistance to both corrosion and wear. It is 100% made in America and completely replaces the factory 5rd tube and 2rd limiter, and thus it is 922(r) compliant.

• Length: 18.25”
• Weight: 8.3oz

Measurements to test Clone Compatibility: 18.25” in total length. Length that sticks out of the receiver when it is installed is 17.5”. Length that screws into the receiver is about 0.75”. Threads have 2mm thread pitch (5 threads per cm). It has a 1” Major diameter (diameter of tube where threaded).

Recommended Wolff Magazine Spring Upgrade:

It is recommended to also upgrade your spring to the Wolff Magazine Spring when upgrading the Benelli M4 extension tube. This spring improves the reliability of your shotgun compared to the OEM spring that comes with your 5-round tube. It has increased power, and also takes up less room in the magazine compared to the Benelli factory spring. The OEM spring is hit or miss; some users say it cycles fine, while others have cycling issues. Usually newer OEM springs work fine, but after being used for some time, they tend to take a set and become too underpowered and start having reliability issues.

Benelli M4 Extension Tube Capacity:

The Benelli M4 magazine extension tubes will fit seven 2-3/4” shells, or six 3” shells. To fit a total of nine 2-3/4” shells or eight 3” shells, you will need to Ghost Load your M4.

Can’t fit 7 Rounds into your Extension Tube?

The measurement of a shotgun shells is the length of the shell after it has been fired (or before it was crimped by the manufacturer). The 2-3/4” measurement is the length of the shell when the crimped walls are flared out after a projectile has passed through it. Some unfired shells are longer than others (They are all close to 2.75” after spent). If you're skeptical, take two different types of ammo and test them side by side on a flat surface.

Unfired 2-3/4” rounds vary in length from about 2.25”, all the way up to 2.5” due to different style of crimping by the manufacturer. Unfired target/birdshot ammo tend to be shorter than high-brass/defensive ammunition. A good rule of thumb is if your shells are longer than 2-5/8”, you won’t be able to fit all 7 shells into your extension tube. However, there are ways to fit seven longer length shells if you don’t want to try different ammo:

1. Install the spring retaining ring only partially to where it’s sticking out of the end of the extension tube. Then, when you reinstall the barrel, the magazine cap will push it down to the maximum position.
2. Remove the spring retaining ring from the end of the extension tube entirely (just remember in the future that the spring will shoot out when you take off the magazine cap if you’re not careful).
3. Upgrade to the Wolff magazine spring which has a slightly shorter, fully compressed length (solid length) than the OEM spring
4. Upgrade to the shell follower which has a slightly thinner design than the OEM follower.
5. Upgrade to an aftermarket magazine cap that has more space for spring retaining ring.

Benelli M4 Extension Tube 2rd installation: 

1. Switch to safe, and remove all rounds from the: chamber, loading gate, magazine tube, and work area. Use proper personal protective equipment.
2. Field strip your Benelli M4.
3. Use snap ring pliers and remove the spring retaining ring (careful, it’s under spring tension).
4. Install the spring retaining ring into the new extension tube.
5. Insert spring and screw on your new extension tube.
6. Reassemble your Benelli M4

Benelli M4 Full Extension Tube 7rd installation: (PDF)

1. It is recommended that you have a qualified gunsmith install this part. We are not responsible for any damage to you or your shotgun. Use proper personal protective equipment.
2. Switch shotgun to safe, and remove all rounds from the: chamber, loading gate, magazine tube, and work area.
3. Remove: magazine cap, barrel, foregrips, retaining ring, magazine spring, magazine follower, bolt carrier group, and trigger assembly.
4. Place the receiver in a padded vice and heat up the OEM magazine tube to melt the thread locker using a heat gun (or torch if you’re careful). Try to only heat the tube and not the receiver.
5. Once the thread locker starts to smoke, use heat resistant gloves and unscrew the tube.
6. Install your new Benelli M4 extended tube the same way it was disassembled and add a drop or two of all metal, high strength thread locker.