[Ultimate Build] Best Benelli M4 Upgrades

The Benelli M4 is the Italian sports car of shotguns, and that fine Italian heritage makes it one of the most dependable and capable shotguns on the market. But even the best can be upgraded, right?

That said, there is one slight problem…this pesky little law known as 922R. This prohibits the shotgun from reaching its peak performance.

Luckily for you, we’re gonna talk about how to fix the Benelli M4 and how to take it from excellent to outstanding (and legal!).

Parts and Pieces for 922R Compliance

Note: We are not lawyers, so don’t take this as legal advice. Always consult an actual attorney with legal questions.

In the U.S., the Benelli M4 comes with some form of fixed stock and a 5-round magazine tube. The gun cannot be imported for civilian sale with the 7-round tube and the famed collapsing M4 stock, which is available to our lucky European firearms enthusiasts.

You can fix it, though, with a few American-made parts and some of that old-fashioned American ingenuity (or Bubba-ing? Let’s call it ingenuity. That sounds better.)

There is plenty of debate on whether 922R is a real issue for gun owners. Plenty of people are happy to point out that no one has ever been convicted of violating it, but as the writer of a public website, I would encourage you to, of course, always follow the law. 

It’s my understanding that to install a higher-capacity magazine tube and collapsing stock, I have to install four American-made parts. 

For more info on 922R compliance, check out our guide!

How We Tested the Best Benelli M4 Upgrades

For this article, I rounded up some parts and accessories and put them on my personal Benelli M4. My goal for this shotgun was to make it the ultimate home defense shotgun, so that was the approach I took when upgrading it to beyond basic. 

Each of these recommendations has been tested thoroughly and chosen based on features, performance, durability, and value.

Best Benelli M4 Parts

1. Mesa Tactical Urbino Pistol Grip Stock

Best Pistol Grip Stock

Mesa Tactical Urbino Pistol Grip Stock – Benelli M4

$0

at MIRA Safety

Prices accurate at time of writing

$0 at MIRA Safety

Ammunition Depot (see price)

Rainier Arms (see price)

Aero Precision (see price)

Show all prices

The problem with Benelli M4 stocks is the length of pull. In the shorter second position, the comb is so high it’s tough to use the sights.

If you want the most effective stock, the Urbino Pistol Grip Stock is for you. This stock features a shorter length of pull, and it rounds out to 12.5 inches in total.

This shorter length of pull delivers a more comfortable stock that allows you to get behind the gun and assume a good squared-up shooting position. The Mesa Tactical Urbino Pistol grip stock still gives you the same pistol grip experience as the intended stock. The Mesa Tactical Urbino Pistol Grip Stock gives you more than a shorter length of pull.

The stock gives you a couple of nice sling points, an adjustable cheek riser for optics, and the same Benelli M4-style pistol grip we all know and love. This stock is a professional-grade option that’s rugged and tough and comes from the shotgun masters at Mesa Tactical.

2. Mesa Tactical Truckee Forend - Best Forend

Best Forend

Mesa Tactical Truckee Forend

$119

at OpticsPlanet

Prices accurate at time of writing

$119 at OpticsPlanet

There are numerous handguards out there that add modularity to the Benelli M4; this includes a Surefire model, one from Strike Industries, and one from Mesa Tactical. Mesa Tactical makes lots of shotgun parts, and one is the Truckee. 

The Benelli M4 Truckee handguard comes in both a standard 8.5-inch model and this fabulous 11-inch model. To install the 11-inch handguard, you have to remove a snap ring that holds on the sling keeper. This install process is not complicated, but the instructions kind of suck, as do the pictures. 

There is no installation guide online either, so you gotta use the crummy included photos. Once installed and put together through the Truckee is quite lovely. It has a slight bit of play, so installing a PEQ 15 and expecting a perfect zero is a fool’s errand. 

Also, hi, yes--it’s a shotgun.

The Truckee 11-inch handguard offers not only M-LOK slots but it pushes them further forward. I wanted to mount my light further than the 8-inch handguard allowed, and I could with the 11-inch model. 

This kit is made from aluminum and features the same darkish-gray finish that the barrel and magazine tube have, which makes it quite aesthetically pleasing. It’s also comfortable to grip and provides a good base for accessory mounting. 

3. Benelli M4 Bolt Assist Device - Best Bolt Assist Device

Benelli M4 Bolt Assist Device

$25

at SJ Hardware

Prices accurate at time of writing

$25 at SJ Hardware

The Benelli M4 features a bolt release a lot like the Grinch’s heart. It’s about three sizes too small. There are plenty of bigger buttons, but one of my favorite fixes comes from SJ Hardware -- the M4 Bolt Assist Device.

This doesn’t replace the button but provides a piece of spring steel that attaches between the handguard and receiver and over the bolt release. This doesn’t provide a replacement bolt release but a huge surface that makes it easier to press.

Not only is it bigger than the stock button, but it's bigger than all the replacement buttons on the market. It’s huge and super easy to press and engage. This makes closing the bolt a blast and will certainly speed up those emergency reload times.

Plus, it won’t empty your pocketbook, and that’s rare to say about anything when it comes to the Benelli M4.

Best Benelli M4 Accessories

Outside of the parts that allow you to rock and roll legally, we have numerous upgrades we’ve made to the M4 to make it a more competent blaster. 

4. Holosun 507C - Best Red Dot

Best Red Dot

Holosun HS507C-V2

$309

at OpticsPlanet

Prices accurate at time of writing

$309 at OpticsPlanet

Brownells (see price)

Primary Arms (see price)

Let’s start with the sighting system I’ve put together. I know I wanted a miniature red dot sight simply to reduce size and weight. Smaller sights allow you to reach over the top of the gun and port load without a big sight getting in the way. 

The Holosun 507C is the optic of choice, and while it’s easy to say I chose it over the Trijicon RMR to save money, that’s simply not true! The Holosun 507C offered me a variety of features that made it a better optic for my purpose. 

This includes some things like the sideloading battery, the easily accessible controls, and the more competent solar panel. The biggest reason I chose the 507C was the reticle. 

Or should I say reticles? 

The reticles include a simple red dot, a 32 MOA circle with a red dot, and a 32 MOA circle. I wanted the 32 MOA circle for a specific reason. Shotguns have spread, right? 

Well, I wanted to use that 32 MOA circle to pattern my buckshot inside of. This way, I know the max range in which my buckshot will stay in that 32 MOA circle. I know the longest shot I’m going to take is about 12 yards inside my home. 

At 15 yards, my chosen buckshot load patterns entirely in the 32 MOA circle. The reticle and perfect zero help me account for the pellets and ensure I know where every single one will land as long as that reticle covers that portion of my target. 

Red dots are also faster than iron sights, and speed is critical for CQB purposes. The Holosun 507C is a durable shockproof optic that seems to have no issues with the gun’s recoil. It’s held steady for nearly 300 rounds of assorted shotgun ammo without a problem. 

It’s light, small, and, best of all, matches the Trijicon RMR pattern for mounting purposes, which leads us to the... 

5. Meprolight Night Sights - Best Sights

Best Sights

Meprolight Night Sights Benelli M4

$83

at Amazon

Prices accurate at time of writing

$83 at Amazon

I already like the stock sights on the Benelli M4 and didn’t necessarily want to replace them. The Meprolight night sights are identical to the stock M4 sights except for the addition of tritium inserts. 

These glowing inserts make finding the sights quick and easy regardless of the time of day or external environmental factors. These sights are easy to install and are made to last. These bright glowing sights are perfect for low light situations and as a backup, just in case my optic dies. 

6. Aridus Industries Universal Q-DC - Best Side Saddle

Best Side Saddle

Aridus Industries Universal Q-DC

$185

at Aridus Industries

Prices accurate at time of writing

$185 at Aridus Industries

The Aridus Industries Universal Q-DC has to be, without any doubt in my mind, the most overengineered side saddle out there. I mean that with nothing but love. This side saddle now rides shotgun (get it) on my Benelli M4 and holds six rounds of buckshot ready to go.

It’s an all-aluminum design made up of two pieces. The first is the base, which attaches to the M4 via an extremely sticky High Bond 3M tape. That sounds sketchy, but trust me, it clings to the gun and will not let go. I’m several hundred reloads into it without a problem.

The second part is the actual carrier. The carrier is detachable and is what physically carries your shotgun ammo. With the press of a lever, the carrier can detach from the base. This makes it easy to refill the base with another carrier on the fly. Those carriers just so happen to fit perfectly in an AR-15 magazine pouch.

The carrier portion features an integral spring that gives you excellent retention over your shells. The Q-DC is the only side saddle I’d trust for carrying my shotgun shells inverted. It might be overengineered, but so is your Benelli M4.

7. Carlson’s Cylinder Bore Choke - Best Choke

Best Choke

Carlson’s Beretta/Benelli Flush-Mount Cylinder Choke

$23

at Amazon

Prices accurate at time of writing

$23 at Amazon

OpticsPlanet (see price)

The Benelli M4 came with an improved choke that was causing all sorts of chaos with a lot of my buckshot loads. I initially assumed it was a cylinder bore, as the website states it should be, but maybe I just got unlucky? 

Either way, a Carlson’s stainless steel cylinder bore choke was a simple addition to clean up my buckshot patterns and improve consistency. It threaded in without an issue and has remained tight over lots of shooting.

8. Blue Force Gear Padded Sling - Best Sling

Best Sling

Blue Force Gear Padded Vickers Sling

$69

at Amazon

Prices accurate at time of writing

$69 at Amazon

Blue Force Gear (see price)

Primary Arms (see price)

Is this a surprise? I mean, I use these same slings for basically every gun build I do. I’ve used one for almost a decade now, and I mean the exact same one. It’s an unbeatable modern two-point sling. 

The BFG Vickers padded sling is very well made and sports a quick pull tab that allows for instant adjustment of the sling to a tight hands-free design to a lose and mobile mode. The extra part of padding increases the comfort of the sling, and the Benelli is not the lightest weapon out there. 

That extra padding is comfortable and worth the additional cost, at least it is to me. 

9. Magpul AFG Gen 2 

Best Accessory

Magpul AFG M-LOK

$0

at

Prices accurate at time of writing

$0 at

The Magpul AFG Gen 2 is a direct-attach M-LOK accessory that mounts to the handguard perfectly. It allows me to pull the gun into my shoulder a bit tighter and increases my ability to control the gun and its recoil. The AFG Gen 2 is more compact and allows for increased control over the gun.

This seems like an instant and easy upgrade and is perfect for the Truckee handguard. It also positions my hand to better use my chosen light. 

10. Surefire Scout Light Pro - Best Shotgun Light

Best Shotgun Light

Surefire Scout Light Pro

$323

at Rainier Arms

Prices accurate at time of writing

$323 at Rainier Arms

Optics Planet (see price)

Brownells (see price)

Grab A Gun (see price)

Show all prices

That Turckee handguard offers you all those M-LOK slots. What’s a shotgunner to do?

Well, you can fill one with the Scout Light Pro from Surefire. Surefire makes bombproof lights, and the new Pro series has embraced a mounting system that allows direct attachment to Picatinny rails and M-LOK slots.

More than that, the mounting system makes it easy to angle the light appropriately to keep the light tight and close to the body of the gun. The Surefire series is well supported by a massive market that makes it easy to attach a variety of tape switches to the gun for easy access.

The Scout Light Pro delivers 1,000 lumens of light and 11,300 candela. That’s enough for a shotgun at shotgun ranges. The light remains small and lightweight, ensuring it won’t weigh you down. The Surefire brand is known for its bombproof design, which will easily absorb the recoil of a 12-gauge shotgun.

Final Thoughts

This Benelli M4 build has been about seven months in the making. I knew after I purchased the gun, I would be spending a whole heck of a lot more money on it. 

That is one thing that should be mentioned. The Benelli M4 is not a cheap gun, and neither are most of the compatible upgrades. The good news is that most of these upgrades are durable, duty-driven designs that aren’t made in questionable locations and are of dubious quality. 

You have to be a real shotgun fan to want to go this far with a gun, and I’m just that kind of fan. I sold guns, parts, and optics to fund it, and I’m still happy with my choice. 

What upgrades would you make? Am I a mad man? Let us know below. Interested in home-defense shotguns? Then check out our hands-on review of the Best Home-Defense Tactical Shotguns!

Latest Updates

May 10, 2024: Removed Geissele Hammer, Scalarworks Mount, Esstac Shotgun Card, STNGR Handguard, and Streamlight TLR RM2. Added Benelli M4 Bolt Assist, Mesa Tactical Pistol Grip Stock, Aridus Industries Universal Q-DC, and Surefire 640U Scout Light Pro. Added supplemental information to each product and also added data on how we tested the gear listed.