
pro_feature
Part one of this series covered Mossberg’s development and release of the 590R and 590RM (box magazine-fed) pump shotguns. Both utilize a rotating thumb safety, reminiscent of those on the AR-15 family of carbines and rifles.
During the second day of the event, we were introduced to their new PRO series of shotguns, built on both the 590 and 940 platforms. The PRO guns are built for hard and duty use.

Long-time friend Jeremy Stafford brought his military and law enforcement experience to the development of the PRO series.
Development
Jeremy Stafford heads Mossberg’s law enforcement and military side. He joined them after a full career at the Los Angeles Police Department, where he worked a variety of assignments – including being a full-time firearms instructor at their academy and a patrol sergeant. More importantly, Jeremy used Mossberg shotguns in ground combat as a Marine Corps reservist in a Civil Affairs role. How that happened is his story, it is worth the price of a drink.

This is a quick pattern check using Federal 9 pellet Flite Control at 5, 15, and 25 yards. What looks like a pellet at 2 o’clock off the bottom circle is not; it’s from something else.
He started by discussing the historical market share data. When it came to law enforcement duty guns, Remington had 75% of the market (the vast majority being 870s). In comparison, Mossberg had the remaining 25%. This line is intended to be in a rack, in a patrol car, or in the hands of working street cops.
Jeremy and everyone else who talked about the PRO series made a point of saying these models were evolutionary rather than revolutionary. Their goal is to put the best gun they can in the hands of those who are, in fact, using it. Everything they did was to make the end user more effective with their shotgun.
An Example
Unfortunately, there have been firearms instructors who attach a weird masculinity to the use of the shotgun. Rather than spend time working with a shooter on mounting the gun correctly and their platform, those people have given inexperienced shooters a shotgun loaded with slugs. The impact of that (pun intended) has long-term, negative effects – especially if the stock is too long and the recoil pad is sub-optimal.
The PRO series uses improved recoil pads, with greater impulse absorption. They have rounded off the top of the pad, making it easier to mount the stock efficiently.

The PRO line includes a detachable magazine-fed breaching shotgun—not the one made for the Allied military organization (PC – Mossberg).
QA/QC
Historically, military contract shotguns have had greater quality assurance/quality control (QA/QC). To meet the intent of the PRO series, they also have the same level of QA/QC. The parts may not all be the same, though, as items on the military contract cannot be replaced.
All parts used in the PRO series will be individually checked and qualified prior to assembly. Individually, not by batch testing. This process will add $100 to the final cost of the guns.
Components
Moving forward from the recoil pad, we get a bantam (formerly a “youth” model) stock. This gives a shorter length of pull and is optimized height-wise for use with optics. This was a previously used model that was brought into the PRO line.
There is a larger, more positive metal safety.
Sights
These guns have two sighting systems. The first is a lower profile, non-adjustable fixed ghost ring sight set. Mossberg believes the fixed style is beneficial. They have not found windage to be an issue when shooting slugs. There are two reasons: a) the range in which they are used and b) the weight of the slug, which mitigates any issues caused by wind.
Their sights are optimized for use with Federal’s LE132 (or similar) loads using the Billings’ (Flite Control or Versa-Tite) shot cup.

Port loading the PRO during a Shoot, Reload, Shoot drill on Gunsite’s Shot Quad. You can also see their low-profile ghost ring sights.
The fiber optic front sight can also be changed out. The staff recommended visiting Hi-Viz Sights when you do this.
Your second option is optics. These receivers are cut for an optic, specifically the Holosun 507K. To install the optic, you will unscrew and remove the rear sight. Then, install the optic per the manufacturer’s instructions or agency protocol.
After-market plates from C&H Precision, among others, are (or will be) available for mounting other optics’ footprints.
Loading Port
One of the most frequently seen modifications to competition or fighting shotguns is an enlarged loading port. Like the magazine well on a pistol or carbine, this modification makes it easier to find the opening and insert the shell.
Along with being enlarged, the edges have been rounded off.
Capacity
How many rounds you load is often a concern with any shotgun. The 18.25” model holds six (6) 2 ¾” shells in the magazine tube and one in the chamber. Those choosing a 20” barrel will get eight (8) plus one. These numbers will delay, to a degree, the onset of reloading. In other words, you will have more time in the fight.
One of the issues Mossberg noted during this project was shell length. Yes, the overall length of these is from the bottom of the brass to the star (or roll) crimp. While SAAMI spec says that is 2 ¾”, they noticed up to a ¼” either way was not uncommon. That impacts the number of shells you can load.
Finish
Instead of being blued or Parkerized, the PRO guns are finished in Cerakote. Why? Mossberg tested a variety of the available finishes currently on the market. They found Cerakote performed better across the board than bluing, Parkerizing, and, yes, even better than their own Marine Coat finish. Additionally, by adopting Cerakote, they keep this in-house, so they do not have to send all the component pieces outside.
You will notice that the PRO series guns are a different color than their previous offerings. They chose Tungsten Grey, which makes them visually different from previous models, but it is still viable in the intended environment.
Final Thoughts
I have watched the quality and durability of the Mossberg guns improve markedly over my time in commercial firearms training. Today, I have zero reservations about recommending the 590A1 and 590 PRO shotguns for any life-saving role – regardless of whether by the police or citizens. Get training on their use and learn how to maintain them!
Part Three will address the 940 PRO SPX semi-automatic shotgun.