Monstrum Side Saddle 12 Gauge Shotgun Shell Holder | Compatible with Maverick 88/Mossberg 500/590/Shockwave Series Shotguns

Fit my Shockwave perfectly. Holds on to the shells firmly, none come lose when firing. Does what it should.

Perfect tactical upgrade for my Mossberg 590. Would buy again.

There is a lack of good instructions with this unit. Good instructions MUST have good pictures. I have a lot of mechanical expertise, so I was able to assemble everything ... it just took longer than it should have. There was too much finish applied to a few of the screws and that almost made it seem like things were cross threading. You just take your time. Having matching nuts for screws makes it possible to chase the screw threads and clean off that over-applied finish. And that is what I did. Not expecting to ever have to remove this holder, I am sure that I will have no further complaints. I do recommend this product ... just be ready for some possible difficulties.

Taking the ejector screw (slotted flat head flat head) out of the inside of the gun was harder than implied. The rest was actually pretty simple. The replacement ejector screw (0.25" longer) had a Phillips cross. It should have been a hex to fit the larger allen wrench included in the kit.The simple instructions on the side of the box should be replaced by an expanded set of instructions on a piece of paper sent inside the box. There would be room for details like TIGHTEN the new ejector screw and get a 9/32" socket to tighten down the nut holding the shell holder to the gun and be sure to put one of the included washers under the nut.I was particularly happy when I wrote MONSTRUM for info about complaints on Amazon in the 1-star area. I received feedback that those were based on an early release addressed a while back. The factory rep (Gerald - GOOD guy!) was correct. This works like a champ and when installed with a full 6-shell load on my Mossberg 500 Tactical Breacher makes a bad-boy gun look like something Satin might carry.

The saddle itself seems to be decently made. Hold shells as it should. The included hardware is garbage though, did not really work with my Mossberg 500. The ejector screw thread pitch is standard and the hardware included is metric. So the m4 screws won't work and you will strip it. I'm trying to figure out the thread for the standard Mossberg 500 ejector screw so I can just buy a better screw online. You can make it work by flipping the ejector screw around so the head is on the outside of the receiver and you have just enough threads to tighten the saddle down. But I'm sure this won't last after a few round will loosen. Once I find a good replacement screw that's a little longer I'll update here.

Ordered this item for, my recent purchase of my Mossberg Maverick 88. Bought this as the combo package with the two barrels, and wanted to stay at a budget point. With that said, I wanted to accessorize it, but not spend a ton of money.I bought the Monstrum side saddle, and didn't have any preconceived notions as to how good it was. When it arrived, I was pleasantly surprised at how solid it was and how nicely built. I honestly just expected a piece of plastic. It has a great metal backing plate.It was also designed perfectly, and lined up exactly with the holes for installation. Easy to read and understand instructions made installation a breeze.After a day at the range, it worked perfectly. Upon cleaning the firearm post shooting, I did realize it was a little loose. That did not surprise me, as the force of 100 rounds through a 12 ga shotgun would knock anything loose. I also never used any loctite on installation. ( hindsight)When I tried to tighten it up, I think I added a little too much force, and probably stripped one of the mounting screws....my fault, not the product.I reached out to Monstrum, to buy replacement screw/pin, so I could remedy this issue. The gentleman asked for a copy of my order ( gave the Amazon screenshot picture) and my address. He never asked for any kind of payment at all.Two days later the parts showed up, and perfect delivery. Outstanding customer service and standing behind their products. I wish all companies were this good. Highly recommend their products.

Screws that came with package are not the right thread pitch for 590. Had to go to a couple different stores to look for ones that would fit!

Mine came pre-owned. OR either with a nasty machining burrito coming of one of the mounting holes. Sent back for refund