3 Ways the Factory Benelli M4 Magazine Spring Fails (And How to Fix All Three)
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The Benelli M4 is widely regarded as one of the most reliable combat shotguns ever produced. But there's one small, often-overlooked component that quietly undermines that reliability: the magazine spring. Failure to feed on an M4 almost always traces back to one of three specific moments, and the factory spring is the weak link at all three.
The Problem with the Factory Benelli M4 Magazine Spring
The OEM spring feels strong right out of the box, but it has a well-known drawback: it takes a set quickly, and it's simply not built with enough margin to handle every stage of the gun's life. That shows up in three distinct ways:
- Break-in on a fresh gun. A brand-new M4 hasn't broken in yet, and the extra internal friction in a stiff, unworn action can be enough for the factory spring to fall just short of fully presenting a shell.
- The 5-to-7-round conversion. Extending magazine capacity means pushing a longer column of shells through the tube. That added length and friction demands more spring power than the OEM spring can deliver, which is exactly why so many shooters notice feeding issues right after installing a magazine tube extension.
- Long-term wear. Even a fully broken-in gun running at stock 5-round capacity isn't immune. Over years of use, the spring gradually loses tension, and eventually it stops pushing shells far enough out of the tube and into the loading gate.
Across all three scenarios, the result looks the same:
- Failure to feed
- Shells contacting the receiver before fully presenting
- Loading gate jams
- Worse reliability with lighter loads and 3" shells
These aren't minor annoyances; for a shotgun that's frequently relied on for home defense or duty use, any one of these failure points can matter at the worst possible time.
How the Wolff Benelli M4 Magazine Spring Solves All Three
The Wolff Benelli M4 High-Power Magazine Spring is built specifically to cover break-in, capacity conversions, and long-term wear in a single upgrade. It's intentionally a bit stronger than needed when new, giving it margin during break-in and immediately after a 7-round conversion, and it holds correct compression longer than the factory spring, so it doesn't fade into unreliability the way the OEM part does.
This results in:
- More consistent shell presentation, from day one through years of use
- Improved feeding under varied ammunition types
- Reduced chance of loading gate malfunctions
More Room in Your Magazine Tube
Beyond fixing the feeding issues, the Wolff spring also has a shorter solid length when fully compressed — about 2.01", compared to roughly 2.11" for the OEM spring. That extra 1/10" of space can be the difference between comfortably fitting 7 rounds instead of 6, especially with longer crimped defensive shells that often exceed standard target load lengths.
For shooters who want to maximize internal room even further, pairing the Benelli M4 Wolff Magazine Spring with a Benelli M4 Max Room Follower (another 1/8" of usable space) and a Benelli M4 Titanium Magazine Cap (1/2" of extra usable space) — for a total of about 0.73" gained over the OEM setup. This extra room in the magazine tube not only allows a larger variety of defensive round crimps, but also reduces compression on the magazine spring for a longer lifespan.
Built for Longevity and Performance
Wolff magazine springs are manufactured from high-carbon spring steel with closed and squared ends, ensuring even seating on the follower and reducing the risk of binding. With more than 70 years of experience dedicated exclusively to firearm springs, Wolff has built a reputation for unmatched consistency and durability — and every Wolff Benelli M4 Magazine Spring is made in the USA, using proprietary materials and processes that set it apart from generic aftermarket alternatives.
Should You Upgrade?
If your Benelli M4 still runs the factory spring and functions flawlessly, testing it at the range is always a smart first step. But if any of the following apply to you:
- You're running a 7-round magazine tube
- You're using defensive or duty ammunition
- Your gun is still relatively new and hasn't fully broken in
- You rely on your Benelli M4 for high-stakes use
...then upgrading to the Wolff Benelli M4 Magazine Spring is a smart, inexpensive way to close off all three failure points at once and add real long-term reliability and peace of mind.