Mossberg 590/500/Maverick 88 QD Side Saddle Shell Carrier by RX Arms: QD vs Fixed, Materials & Fit Guide

One of the top upgrades for the Mossberg family of shotguns Mossberg 590/590A1/500/590 Shockwave/Maverick 88.  A side saddle shell carrier, its always a wise idea to carry extra ammo on your firearm for when you need it most, and having the ability to remove that side saddle for a reload, or for storage, is the main advantage of our QD system.  In this post I’ll go over the receiver footprint of the Mossberg 590 (same as the Mossberg 590A1, Mossberg 590 Shockwave, Mossberg 500, Maverick 88) specs for the RX Arms QD Side Saddle Shell Carrier system.

 

Why Mossberg 590/500/Maverick 88 Owners Should Use A Side Saddle

As stated above, the main reason for using a side saddle/shell holder on the Mossberg pumps is to carry extra ammunition on the gun so that it is there when you need it.  If you use other methods to carry ammunition like a pouch, or other alternatives, if you are under duress and picking up your shotgun, you may forget this pouch.  It is best to have something attached to the firearm so that it is ready to go when you pick up the shotgun.  Simple as that.

Quick Detach vs Fixed Side Saddle vs Velcro Shotshell Card for the Mossberg 590/500/Maverick 88

The obvious advantage of our QD system is the ability to remove the shell carrier/shell holder from the gun.  This is useful for transport in the vehicle, stowing in a safe, and also being able to reload the shell carrier when the one on the firearm goes dry.  You should alway feed your shotgun constantly, and not wait for the magazine to run empty.  This ethos especially holds true for pump shotguns.  You do not want your mag to get empty on a pump, loading the open chamber with a shell before loading the magazine tube is more time consuming than doing the same procedure with an auto loading design.  This can be avoided if you constantly top off your magazine tube as you consume ammunition.  When our QD Side Saddle is dry, you can reload it immediately if you are carrying spares on your body.  We go more into depth on Rigid and other shell carrying systems on post Rigid Side Saddles vs Velcro Shot Cards: Why a Quick-Detachable (QD) Hybrid Makes Sense

Materials — What our Mossberg 590/500/Maverick 88 Side Saddle Is Made From

We use premium materials that are meant to endure bumps, impacts, and extreme temperatures.

• QD Shell Carrier Body: High Glass, High Performance, injection mould polymer is utilized for the Shell Carrier body.
• Mounting Plate & Button Latch: Premium 7075-T6 aluminum is utilized for the Mounting Plate (which remains fixed on your receiver), and for the button latch which is on the shell carrier body.

These materials are purpose chosen, to ensure our shell holder will endure anything you throw at it.

Mossberg 590/500/Maverick 88 Fit & Compatibility — Handguard/Forend Clearance, Receiver Pins/Screws

I will say that the receiver design of the Mossberg 590/500/Mav88 family had a large part to play in the design of the mounting plate.  I had to be sure that the mounting plate adequately cleared the extractor screw, trigger group take down pin, and elevator assembly arm that are exposed on the side of the receiver.  With this in mind, the allowable setback I we are able to achieve on this family of shotgun receivers is around 0.42″.  This distance is limited by the elevator assembly arm, and the trigger group take down pin.  We also needed to be sure the serial number would be exposed, which we did.

Our Mounting Plate is compatible with all the OEM tactical handguards for these models.  As always, we recommend using our template to print off and confirm fitment if using an aftermarket handguard that overlaps onto the receiver .  You can find the printable template on the QD Side Saddle Shell Carrier product page to confirm fitment.

We designed the Mounting Plate to provide adequate clearance for many shotgun receivers including of course the popular models Mossberg 590, 590A1, 500, Maverick 88.

Mossberg 590/500/Maverick 88 QD Side Saddle Shell Holder Installation

You can follow our installation guide found on the product page for our QD Side Saddle Shell Carrier.  In general, you just want to leave your take down pin, extractor screw, and elevator arm exposed so that you can easily remove the trigger group and other components from the firearm for cleaning.

RX Arms Mossberg 590/590A1/Shockwave/500/Maverick 88 Side Saddle Shell Carrier – FAQ

Will the Spare QD Shell Carriers fit into AR15 mag pouches?

Yes, they will fit into most AR15 mag pouches on the market.  More Specifically tested, the HSGI Taco is designed in a way that it can easily expand to accept a thicker shell holder like ours.  Also, the Esstac KYWI AR15 mag pouches will need the Kydex to be modified to give less squeeze to use with our spare carriers, it can be done, but the fit is very tight as it comes new.  As for other brands, our experience is that there is no fitment issues, however we can not guarantee fitment every any magazine pouch as there are simply too many variants out there.  RX Arms will be offering their own pouches in the future as well.

How does the mounting plate attach to the receiver?

The mounting plate attaches via 3M VHB Adhesive.  More information can be found on the product page.

How are the shells retained?

We use a proprietary rubber blend dual strips.  These two strips are designed to give an easy pull, but also robust retention in all weather conditions.

How long will 3M VHB last?

3M VHB is currently in use in the Aerospace and Transportation sector to replace rivets and welds.  3M Documentation from long term outdoor exposure in harsh environments like Arizona resulted in the 3M VHB retaining 90% of its strength.  We are talking outdoors every day exposed to sun, and UV rays, for 10 years.  If combined with indoor storage of firearms, the data suggests that the 3M VHB bond can last 10-20+ years.

How well does the QD Side Saddle stand up to bumps and impacts?

We have done extensive testing on impacts, and drop testing with a mock gun weighing 9.3lbs.  The 3M tape (and carrier) did not have any problems during these tests.  We will do a blog in the future detailing the processes we used when destruction testing our unit including many multiples of strikes with a hammer.  I will say, in wanting to make the VHB fail, it did take a slew of hammer strikes on the unit, before the 3M VHB did tear in half.  These conditions will never happen in real life, but it proves how incredibly resilient the VHB bond is.