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

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.

This side saddle fit my Mossberg 500 12g perfectly as advertised. Because my gun's forearm is the long version (which helps with my short stature...), I cut the front shell holder off and drilled a new rear mounting hole. The front end has 2 mounting holes, and I used the "wrong one" to move the whole shell holder back a little more. I'm very happy with it, and I used it in a defensive shotgun course last weekend. I am a certified shotgun instructor and FFL dealer. This is good equipment. The shell tension is just right, and you can place shells brass up or down without them falling out.

DO NOT BUY!!! Mossberg 500 and maverick 88 this DOE NOT WORK, the longer replacment screw for the extractor is the wrong size, as others have stated, this ruined my maverick 88, screw is wrong thread and stops the bolt from cycling a round because the poor quality and wrong size screw monstrum supplies catches on the round, DO NOT BUY, I contacted momstrom and never heard back, returnee to Amazon

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 actual holder itself is fine. Seems to retain the shells adequately. The included hardware is questionable. The inclusion of a bunch of extra screws, nuts, and washers coupled with the minimal instructions make installation a bit confusing. Biggest let down is the main screw for threading through the receiver. It just didn't feel 'right', and i was worried i might damage the threads in the receiver. The phillips screw started to strip a bit with only a bit of force. So I abandoned the installation until I can source a proper screw to replace it.

It's made of plastic for the shell holders and the backing is metal. Shells fit into them nice and snug, but not too snug to where it may snag. My only complaint is that it covers the serial number and it was not compatible with my original forend. I had to buy the Magpul forend for it to work properly.

Bought for a mossberg maverick. Worked perfectly. Good quality materials. Easy install

It fits good just get a small sturdy Phillips screwdriver to tighten screws inside the trigger area and be sure to use blue lock tite on the screws to keep secure and not come loose other than that it’s a great fit on my Mossberg maverick 88