Mossberg 930 Shotgun Upgrade Guide
August 08, 2016
On paper, few firearms can compare to the raw power of a semi-automatic shotgun. Complexities arise when shooters discover that quality models are often prohibitively expensive and require extensive break-in periods. This makes picking both a defensive and competition shotgun a truly daunting task.
One way to simplify the process is to choose a shotgun capable of filling multiple roles: a semi-automatic scattergun appropriate for protecting livestock, defending loved ones and competitive shooting sports. Problem is, most shotguns suited to one of these roles often fall short in the others.
The solution? Purchase a reliable, inexpensive automatic shotgun with extensive aftermarket support and tailor it to your needs. My choice is a Mossberg 930 JM PRO. A competition-ready 12-guage semi-auto shotgun built on Mossberg's standard 930 action. As it ships, the 930 isn't quite ready to meet the demands of shooters in search of a turn-key solution to their shotgun needs.
Thankfully, with a few choice upgrades, shooters can own a quality shotgun on par with offerings from other makers without spending two grand.
Mesa Tactical Urbino Stock
My first upgrade is a controversial one, at least on Mossberg shotguns: a Mesa Tactical Urbino pistol grip stock. This is a controversial upgrade because pistol grip stocks don't play as nicely with Mossberg shotguns as they do with Remington ones. Not because they don't function correctly but because of the location of the Mossberg's safety.
On other shotguns, the safety button is located on the trigger guard. In this location, a shooter can either engage or disengage the safety with the trigger finger without shifting their shooting grip. On the Mossberg, the safety is situated along the tang. This is an ideal location for use with traditional stocks. With those, the shooter simply needs to shift their shooting hand thumb to the top of the tang to toggle it.
When paired with a pistol grip, the tang safety necessitates removing the shooting hand from the pistol grip entirely. Not a huge concern, but it's something to be aware of. Thankfully, the many advantages of the Urbino stock far outweigh the ergonomic woes of its safety's location.
For me, the two biggest improvements the stock offers are its reduced length of pull and inclusion of limb-saver recoil pad. The pad does a great job of reducing the hefty felt recoil of full-power defensive ammo like double aught buck. Though truthfully, the reduced length is far more beneficial to my household.
Both my wife and I are fairly short-statured. While I've grown accustomed to running ill-fitted shotguns, she has not. The reduced LOP allows her to better square off against the gun's recoil with a bladed fighters stance. It also shifts the balance back towards the shooter, allowing for easier one-handed manipulation.
Further in this vein, the pistol grip itself is ideal for navigating interior spaces, while freeing up the support hand to toggle light switches, open doors or escort loved ones to a safer location. Also, the Urbino includes multiple rear sling mounts and a cheek rest adjustable for comb — perfect for use with optics.
Meopta Meosight III
Speaking of optics, running a reflex sight on a competition gun may elevate you to the more challenging unlimited division. In a home defense scenario, though, it can give shooters an edge over armed home intruders. Due to the enormous variety of red dots and holosights on the market today, deciding on one often seems overwhelming.
Personally, I wanted the smallest, lightest optional available; one that wouldn't get in my way during reloads or snag on my clothing when in confined spaces. While a myriad of optics fitting this description are available, fewer are both affordable and reliable.
The company I decided to go with is a small, but growing, optics maker from the Czech Republic: Meopta. Boasting some of the brightest scopes on the market today, Meopta builds many of the entry-to-mid-level optics sold by high-end glass makers in the US.
One Meopta product in particular struck my fancy a few months back, when I spotted it at Meopta's SHOT Show booth — the Meosight III.
Tipping the scales at a featherweight 1.3 ounces, the barely two-inch high reflex sight is small enough to lose in the cushions of a sofa. Normally, having an optic this small and low can be a pain to use on rifles and carbines. On a shotgun, it's a different story.
Given the low profile of shotgun bead sights, the Meosight III is a perfect fit for the Mossberg 930. So much that shooters who opt for factory furniture on their 930 can use the optic without issue, even with standard comb height. This, combined with its impressive 300-hour battery life from a single CR2032, means shooters won't have to worry about a dead optic in their time of need.
GG&G Tactical Bolt Release Pad
The factory bolt release button on the Mossberg 930 is about the size of the magazine release button on an AR15. It's not tiny by any means, but it can still be challenging to actuate in total darkness or stressful conditions. Whether those conditions are the screech of a shot timer or the shattering of a window in the dead of night, making that button easier to find is crucial.
The best solution I've found is the Tactical Bolt Release Pad from GG&G of Arizona. Made from aircraft-grade anodized aluminum, the oversized release is not only easier to locate but also easier to use. This is due to the button's proprietary design. The button acts like a giant seesaw lever, giving increased mechanical advantage to the shooter's thumb.
The only downside to the release is installing it. Changing the magazine release button on a Mossberg 930 requires three hands, a tiny flathead screwdriver and copious amount of patience. Word to the wise: If you're going to break down the internals to install this piece anyway, give your receiver a nice deep cleaning.
This pad is crucial for shooter's with extended charging handles, as the original is small enough to place a shooter's knuckles precariously close to the action as it slams forward to chamber a round. The pad allows a user to release the bolt with the fingertips of their support hand instead of their thumb. It makes a great combination with another product from GG&G: the Tactical Charging Handle.
GG&G Enhanced Charging Handle
The 930 I used for the basis of this article already featured an extended charging handle, but the inclusion of GG&G's Bolt Release Pad calls for something a little bigger.
Enter, the Enhanced Charging Handle — and by enhanced, GG&G means enlarged.
Though in all fairness, this is an enhancement. The larger charging handle makes extracting jammed rounds infinitely easier by giving a shooter greater perch for their hand. The handle also affords shooters a superior grip to most factory 930 handles with its aggressive knurled exterior.
It can be a little rough on your hands, but shooters with oily or sweaty hands are still able to get a solid grip on the handle to either charge the action or clear a malfunction. The handle is made from phosphate-coated 4140 ordnance steel heat treated to Rockwell 45 C. If a shooter manages to break one, then they meant to.
Installation of the handle is straightforward and requires no modification or fitting to either the handle itself or the host shotgun. Also, despite its steel construction, the handle is as light as the factory handle as well as being more durable. This handle is a must for three-gunners running a 930 in competition.
Mesa Tactical Magazine Clamp
If you're wondering what on Earth a magazine clamp is and why a shooter would want one, you're not alone. Mesa Tactical's Mag Clamp doesn't sound like anything spectacular based on its name, but what it brings to the shotgun is truly invaluable.
The steel Magazine Clamp replaces the stock clamp that 930s with extended tubes often ship with. The original clamp is designed to prevent the tube from bending or becoming misaligned by keeping it parallel to the barrel. This is crucial if a shooter runs a shotgun whose magazine tube extends past their muzzle, as extra flex could cause the shotgun to blast its own magazine off.
So why replace the existing one?
The one offered by Mesa does more than simply act as a clamp. It also includes two Picatinny rail segments and ambidextrous quick-detach sling mounts. While I personally don't like running a sling on a home-defense shotgun simply because it can snag on objects in a home, they hold merit. Sometimes, a shooter needs both hands free to pick up small children or startled pets.
Though, this is secondary to its most important role — serving as a light mount.
Streamlight TLR-1s Tactical Light
As an owner of three different versions of the TLR-1, I'm familiar and equally fond of these ultra-bright, affordable tactical lights. In particular, the TLR-1s is my go-to long gun tactical light.
Blasting a retina-searing 300 lumens out past 75 yards, the 'S' version of the TLR incorporates an enlarged, bell-shaped bezel. This concentrates and directs the light's hotspot, allowing it to function as both an illuminator and makeshift aiming device.
But the greatest benefit to a tactical light is target identification. While the occurrence of friendly fire in the home is gravely overstated by those opposed to private firearm ownership, it is still a very dangerous possibility. Plus, if a shooter intends to follow the four rules of safety, verifying a target is absolutely crucial.
One upgrade I would recommend for the TLR-1s is the rifle kit. It consists of a replacement for the rear battery panel of the light and a pressure switch that can be mounted further back on the 930's handguard.
Nordic Components MXT Modular Magazine Tube Extension
Shotguns are immensely potent firearms. In close-quarters fighting, nothing boasts the same fight-stopping power of a 12-gauge shotgun loaded with quality buckshot or slugs. The biggest downside of shotguns is keeping their magazine tubes full of fresh rounds.
While bandoliers, shell carriers and side saddles are great, increasing the firearm's internal capacity is even better. Some shooters like IPSC, IDPA and 3-gun champion Jerry Miculek take this to the extreme with enormous two-foot magazine tubes holding dozens of rounds. This works great in the open spaces of a 3-gun match, but it is nigh impossible to navigate the inside of a home with one.
A better solution is a Nordic Components +4 MXT Magazine Tube Extension. This tube raises the 930's internal capacity to a staggering 9 rounds of 2 and 3/4" shells, and allows shooters to replace the tube itself with shorter or longer options depending on their personal needs or state-regulations.
The Mossberg 930 I modified actually shipped with the +4 extension installed, and has fed my test shotgun without issue for well over 600 rounds without cleaning. While I don't recommend this, it's good to know that if a shooter finds themselves in a dire situation where cleaning isn't possible, the 930 will still function just fine.
OR3GUN Marine Spacer Tube
The only thing better than an extended charging handle for clearing a jam is avoiding the malfunction altogether. So when my Mossberg 930 began stuttering on low-brass birdshot, I hit the Internet in search of a solution.
That's when I stumbled upon a strange YouTube video by OR3GUN showcasing their Mossberg 930 encountering the same failure to eject issues mine had. Now, given that my 930 had over 500 rounds of ammo through it since its last cleaning, I decided to install the OR3GUN spacer and see if the part could enhance its reliability with under-powered ammo.
Before I get to the results, it's important to understand what the spacer is, and what it accomplishes. The Marine Spacer Tube replaces the solid factory spacer with an anodized, ventilated one. The OR3GUN spacer permits transient gas that is normally forced through the system, fouling up the action, to be vented away from the shotgun's moving components.
Under ideal, factory-new conditions, this isn't a problem. But once the gun builds up any carbon, moisture or both, the gas system loses power and doesn't cycle as reliably. Shooters using three-inch buckshot or slugs won't have any issues since the ammo is so powerful. But if you intend to run reduced-recoil ammo, OR3GUN's Marine Spacer Tube is an absolute necessity.
GG&G Enhanced Magazine Follower
While I wouldn't quite qualify GG&G's expertly-made follower as a 'must' for the 930 series, it's an upgrade I've grown so accustomed to that shotguns without one seem primitive by comparison. No, not simply for the fact that the enhanced follower's design allows for water, dirt and debris to be more easily removed from the magazine tube.
No, my favorite part about the little anodized puck is the finish: bright red anodized aluminum. The color is very distinct, and it makes verifying an empty magazine tube much easier. It's not just easier for the shooter either but also for the RO or match safety officer at 3-gun events, many of whom are volunteers with less than perfect eyesight.
Defensive users benefit from the bright color as well, but more pragmatic users who trust tactile conformation over visual will be happy to learn the follower feels very different from a shotgun shell.
Winchester PDX-1 12 Defender
Winchester's line of PDX-1 ammunition is purpose-built from inception for defensive use, and the 12-gauge variety is no different. Normally, Winchester's PDX ammunition is simply a new take on an old favorite: taking a proven load and giving is more reliable, regular expansion.
On the PDX-1 12 Defender, Winchester combined the two most effective shotgun loads into a single, hard-hitting solution for anything on two or four legs within 50 yards. The PDX-1 Defender incorporates both a 1-oz rifled slug and three 00 buck pellets in a single shell.
This is presumably to give the advantages of slug ammunition — instant fight-stopping power, longer effective range — and the safety net of using buckshot. How does it fare? Well, it's inarguably superior to standard slugs for self-defense, since the load still propels that massive 437-gr. at a blistering 1150 fps, but with the addition of three 55-gr., .33 caliber pellets.
Shooters who opt for slugs in a home-defense scenario need to consider their surroundings and other family members. Shotgun slugs are renowned for their ability to pierce anything from thick bear hide to brick walls. As such, this load is inappropriate for use in apartment buildings, or domiciles with multiple occupants, as their safety cannot be ensured.
For country folk, and those living either alone or with their loved ones nearby, few loads can offer the impressive 'oomph' of Winchester's PDX-1 12 Defender round.
Mesa Tactical Sureshell Aluminum Carriers
As I've stated before, keeping a shotgun fed is, by far, the most difficult portion of running one in competition. In comparison to magazine-fed rifles, shotguns hold dramatically fewer rounds. Furthermore, the size of these rounds makes stuffing some inside a pocket cumbersome, and their tendency to move while in said pocket means having to reorient them after retrieving them.
A better solution is to keep a few handy in a Mesa Tactical Sureshell side saddle attached to the shotgun. Mostly because doing so ensures the spare rounds are always in close proximity to the firearm itself. There's just one small problem with running a 930 with a side saddle — it can affect reliability.
If overtightened, the screws replacing the roll pins running through the receiver can cause the action to bind. This fact made me initially reluctant to recommend one to readers. Thankfully, I discovered the answer to the issue while installing the Chicago screws the Mesa carrier uses to mount itself to the 930. (Chicago screws consist of a male and female screw that thread into one and other.)
My solution is fairly straightforward — add a single spring coil between the screw head on the left side of the receiver and the washer that makes direct contact with said receiver. Doing so prevents the screws from being overtightened, loosening themselves during recoil and from exerting too much force on any part of the receiver's sidewalls.
If you're worried about finding a good spring to use, I found that a single coil of a firing pin spring from a Glock 17 works perfectly. So next time to replace the springs in your Glock, don't discard the old spring.
The carrier itself is made of aircraft-grade aluminum and includes three different rubber tubes that adjust the tension on the shells in the saddle. After some experimentation, I found installing a singular medium-strength tube was perfect for keeping shells secure, but easy to retrieve.
Before committing to a setup, shooters should test their desired defensive shells in the carrier, and try doing some jogging/jumping jacks with a few in the carrier (though otherwise keep the gun free of ammo). Adjust until secure.
While any variation of the 12 gauge Mossberg 930 makes for an effective defensive weapon when paired with proper ammunition, understanding its shortcomings is crucial to successful employment of it. Whether your solution is to simply train around these issues, modify the gun or purchase upgrades, the two most important factors in you and your loved one's survival is attitude and practice.
The best shotgun in the world isn't worth a damn if a shooter doesn't know how to use, or isn't willing to. Prepare the mind beforehand, and practice with your chosen defensive firearm every time you visit the range. If the unthinkable ever happens, it's easy to fall back on training, but only if you have any.