Monstrum Side Saddle Shell Holder with Picatinny Rail Mount for Mossberg 500/590/Shockwave Series Shotguns

It installed very easy and fits perfectly. It doesn't cover the safety or go past the chamber over the barrel on a Mossberg 590 12 ga shot gun. The 6 shells are held in tightly yet I didn't have any problem removing the 6 shells and reloading. The bad reviews are not accurate. I read all the negative reviews and was concerned after I purchased the item, but I figured I would give it a shot (Pun intended). I thought if it doesn't fit I will return it but it can't hurt to try it since there are so many good reviews. It goes on so easily I was pleasantly satisfied. It took me 5 minutes to install and I didn't need longer screws or any "LOCK TIGHT" to install it and snug it down securely. All the screws and the allen wrench came in the box that I used to install it. I will say though "WHEN ORDERING MAKE SURE YOU CLICK ON THE 12 GA OR 20 GA MODEL BEFORE COMPLETING THE PURCHASE". I think that is what throws people off to get a negative review because they receive the wrong caliber shell holder (12 ga 6 shell holder or a 20 ga 7 shell holder, that also threw me off in the description compared to the picture provided they have to describe the item on the Amazon page). And they do not realize it until they receive it and some people after receiving it. I ordered the product then had to cancel because it was set on the 20 ga, It was easy to cancel that order and reorder the 12 ga model. I don't have a picture but it fit perfectly on my Mossberg 590 12ga as pictured on other good reviews.. Sturdy metal and polymer material, built to last and take some good hard working abuse !!! I AM VERY HAPPY WITH THIS ITEM , IT IS JUST WHAT I WANTED !! I will order again if I get another Mossberg 500, 590 or 590A1 12 ga.

I have done business with them before, and I will do business with them again absolutely excellent products in their customer service this second to none I would highly recommend purchasing their products

Great little add on to the shockwave lazer style. You have to mount on the left side because of the laser. But doesn’t throw the balance off, when Pummeling targets. Great little piece.

Works great looks great.

Amazingly, this product does exactly what it says it will do. First of all, let me comment on the ease of installation. Four long screws take the place of the filler screws on the top of the receiver. This item is in 2 pieces. The Pic rail is one part and the shell holder the second part. The shell holder in held in place by the 4 screws that hold the Pic rail to the receiver. A very secure mount. One thing that is different than the picture of the item is that the bevels are actually beveled down. Shown in the ad the bevels are up. I wondered about that but the one I received had the bevels on the bottom side. As they should be. Love the item and although I would have liked to see it less expensive, it turned out to be well worth the money. I have pictured it mounted on my 590 but they make them for a bunch of tactical shotguns.

This product is fantastic! The material is incredibly strong, yet the gun still feels surprisingly light. Installing the slide was a breeze; it fit my 535 perfectly. To top it off, the appearance it gives my gun is incredibly sharp.

I have a Mossberg 500 ATP with an H code series number which indicates it was made in 1983. I didn’t look at it prior to ordering this side saddle. Unfortunately my receiver is not drilled or tapped for mounting this product. The product is well made and has all the appropriate screws to mount on a drilled and tapped receiver. I was disappointed it didn’t fit. I returned it to Amazon with no problems, and bought a sling which holds 15 shells. Great product buu check your 500 receiver for screws before you order. This does not fit all 500’s.

Great holder! Easy install. Firm grip on shells. Looks great.