When it comes to shotguns, I generally prefer traditional stocks—I believe “Monte Carlo stock” is the term. There are several reasons for this. Primarily, most shotguns are designed for a standard stock and pistol grip, and stock adaptations can be problematic, especially with Mossberg shotguns due to their tang safety. However, that’s now changing with the 590R series.
The Mossberg 590R series is derived from a breaching shotgun developed for the British Special Operations Community. The significant change with the 590R is the safety placement. Bid farewell to the tang safety and say hello to an AR-style safety mounted on the side of the receiver. Mossberg maintained the ambidextrous ideal and specifically designed the 590R series to work seamlessly with pistol grips.
Diving Into the Mossberg 590R
The new safety placement positions the rotating safety precisely where your thumb naturally rests when gripping the pistol grip of the Mossberg 590R. It’s a metal safety that will feel familiar to anyone who has used an AR-15. A safety located on the side of a Mossberg shotgun might seem prone to accidental manipulation by the user’s gear.
Mossberg anticipated this potential issue and integrated a shielding device into the stock and pistol grip setup. This shield creates a protective “cliff” that runs over the top of the gun, safeguarding the safety from any unintended forces that could inadvertently switch it from safe to fire.
The stock design is distinctly Mossberg. It’s clearly inspired by the AR receiver extension and stock, but it’s a one-piece system, which is a superior design for shotguns. I’ve broken several adapters and bent a few receiver extensions near the threads enough to know that a hollow aluminum tube isn’t robust enough to withstand 12-gauge recoil for long.
Their included stock is pure, beefy polymer and solidly connected to the gun. It’s a six-position adjustable design, allowing for on-the-fly length of pull adjustments. The stock itself can be replaced with any MIL-SPEC AR-15 stock if desired. Mossberg’s proprietary design features a rather nice built-in recoil pad. The gun also accepts AR grips, and while the included grip is perfectly adequate for me, it can be replaced.
Beyond the Safety
While the safety is a major highlight, it’s not the only noteworthy feature. Mossberg produces both a standard model and an “M” model, with “M” denoting the magazine-fed versions. The pistol grip design significantly benefits the magazine-fed variants, making magazine changes much easier compared to a traditional grip.
The gun comes with a heat shield that sits a fair distance off the barrel and works extremely well. It’s also more securely fastened than any other heat shield I’ve encountered. It does an excellent job of protecting your hand. Like other Mossberg shotguns, it’s optics-ready and comes with the rail pre-installed, practically begging for a red dot sight.
My model includes flip-up Magpul sights, which are rifle sights on a shotgun. Mossberg’s new pump design is trim and slim yet perfectly usable. This tube-fed model holds six rounds and comes with an M-LOK tube-to-barrel clamp that isn’t strictly necessary but provides a convenient slot for a light or sling point.
The trigger group is entirely metal, which is an interesting touch, typically seen on the 590A1 series. The Mossberg 590R series is well-built and clearly oriented towards tactical use, though I wouldn’t be surprised if they produce a turkey hunting model in the near future.
At the Range
The Mossberg 590R may be a 12-gauge, but its recoil is manageable. The rear pistol grip offers several benefits, particularly concerning the “push/pull” method of recoil reduction. The grip allows you to pull the shotgun tightly into your shoulder and maintain solid pressure while firing.
Additionally, much like an AR, the gun now utilizes an inline stock. This design helps reduce muzzle rise and directs recoil straight back, rather than back and up as with a traditional shotgun stock. The difference is noticeable.
The stock and its adjustable length of pull make it easy to get behind the gun without it feeling cumbersome. I typically use position two, which is perfect for me. Another benefit I’ve found is easier reloading. It’s simpler to hold the gun up and on target, as the rear pistol grip makes it easier to manage the weight while feeding shells into the tube.
With that in mind, it’s also easier to perform any task with one hand while holding the gun. Opening doors, using a cell phone to call the police, etc., are all more manageable when you have a vertical grip on the firearm.
The Mossberg 590R’s sights can be a bit of a pain. Using the small peep of a rifle sight isn’t ideal for speed, and shotguns are often about speed. I ended up folding the rear sight down and using only the front sight, which yielded excellent results. Ultimately, a red dot is the way to go with these guns.
Running the Gun
The safety works quite well. It’s audibly “clicky” and responsive, moving in and out of position easily—just like an AR safety. My only complaint is that in the “fire” position, the tail of the safety rests against my trigger finger. When firing full-power loads, it can rub and become irritating. Reduced recoil loads, birdshot, etc., don’t pose this problem.
As expected, the gun is reliable. It feeds, fires, and ejects everything I’ve put through it. I fired mostly birdshot, but also a good amount of buckshot and several boxes of slugs. Everything cycled without a problem. It could even be a mini-shell gun with an adapter if you choose.
One downside is that with an inline stock, you’re now using taller sights. This creates height-over-bore issues at close range, where a shotgun truly excels. I’d advise using a large ring reticle on a red dot that can help compensate for this issue. With regular buckshot, it’s not overly noticeable, but with certain loads like FliteControl, it can create several inches of point-of-impact difference.
The 590R and You
The 590R finally provides a shotgun specifically designed and intended for use with a pistol grip and AR-style stock. It has been developed from the ground up to work with a rifle-type stock. The primary benefit I see to this design is making the transition to a shotgun much easier for individuals who are already proficient with the AR-15 platform.
While I won’t be swapping all my shotgun stocks to pistol grip designs, it’s refreshing to see Mossberg try something different and execute it successfully, with only a few minor quirks.
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