Why Your Benelli M4 Often Only Holds 6 Rounds, Even with a 7-Round Tube (And What You Can Do About It)
The Benelli M4 is one of the most trusted semi-automatic 12ga shotguns on the market: rugged, reliable, and battle-proven. Yet one common frustration among shooters is magazine capacity when running longer defensive 12-gauge shells. Here's why it happens and how a few simple upgrades can help you get the most out of your M4's capacity and reliability.
12ga Shell Lengths: Not All 2¾" Shells Are Created Equal
Shotgun shells are categorized by length, such as 2¾", 3", and 3½". But within the same nominal length, loads can vary physically depending on how the crimp is formed. The 2¾" figure is the length of the hull before it's crimped, so two 2¾" shells from different companies can end up with noticeably different overall lengths.
- Defensive rounds (rolled crimps): These often use a rolled crimp that makes the loaded shell longer overall.
- Target or sporting rounds (folded crimps): These usually use a folded crimp that keeps the shell shorter and more compact.
Even when both are marked 2¾", a rolled-crimp round can be significantly longer than a folded-crimp round. The M4's magazine tube is already tight, and those extra millimeters add up. The usual result:
- 6 rounds load smoothly
- The 7th round won't lock in all the way, no matter how hard you push
This is especially noticeable when trying to load 7 defensive rounds into a nominal 7-round tube.
Why the Benelli M4 Magazine Tube Struggles
The Benelli M4 uses a fixed tubular magazine designed around roughly 58mm of length per round. Defensive ammo with longer rolled crimps can:
- Exceed 62mm in length
- Reduce the total usable space in the tube
- Cause binding, overlapping coils, or magazine spring damage and wear
- Prevent you from reaching the full 7-round count
Even if the spec sheet says the tube holds 7, real-world shell length matters.
Upgrade Solutions for Full Capacity and Smooth Feeding
The good news is there are reliable ways to help the M4 reach full capacity with longer defensive shells. These three upgrades work together to free up tube space, reduce stack pressure, extend spring life, and make that 7th round actually fit and load more easily.
Benelli M4 Titanium Magazine Cap
Replace your magazine tube end cap with a lightweight titanium cap that reduces weight at the muzzle and adds room inside the tube.
- Frees up 0.433" (11mm) of usable space in your magazine tube when used without the spring retaining ring
- Reduces binding on the last round
- Adds strength without adding weight
Learn more → Benelli M4 Titanium Magazine Cap
Benelli M4 Max Room Follower
The Max Room Follower is a complete redesign of the OEM Benelli M4 follower. It's built to take up as little room as possible in the magazine tube and is shaped to help long defensive rounds seat properly.
- Adds 0.177" (4.5mm) of space in the tube compared to the OEM follower
- Ideal when longer crimps would otherwise keep you from full tube capacity
Grab it here → Benelli M4 Max Room Follower
Upgraded Benelli M4 Magazine Spring (Wolff)
A strong, high-quality replacement magazine spring can make all the difference in consistent feeding.
- Adds 0.098" (2.5mm) of magazine tube space thanks to a shorter solid length than the OEM spring
- Extra spring force keeps pressure on the follower with longer or heavier shells
- Works especially well combined with the Max Room Follower and titanium cap
Check it out → Benelli M4 Upgraded Magazine Spring
Combined Gain
Run all three together and you free up about 0.709" (18mm) of tube space compared to the factory setup.
|
Upgrade |
Space Gained |
|---|---|
|
0.433" (11mm) |
|
|
0.177" (4.5mm) |
|
|
0.098" (2.5mm) |
|
|
Total |
0.709" (18mm) |
Final Tips for M4 Shooters
- Line up your ammunition on a flat surface to see which rounds are longer than others.
- Test your specific defensive loads, since some will fit more easily than others.
- Combine all three upgrades for the best chance at true 7-round capacity.
- Always cycle your shotgun after any magazine hardware change to confirm reliable feeding.
Wrap-Up
The Benelli M4 is capable of seven-round capacity, but real-world ammo dimensions, especially the rolled crimps on defensive shells, often prevent it without modification. With the titanium magazine cap, Max Room Follower, and upgraded Wolff magazine spring, M4 owners can unlock full capacity and rock-solid reliability, even with longer defensive 12ga rounds.