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The Monstrum Side Saddle Shell Holder is a precision-engineered polymer accessory designed exclusively for Mossberg 500, 590, and Shockwave shotguns. It securely holds up to six 12-gauge or seven 20-gauge shells while providing a Picatinny/Weaver rail for mounting optics. Installation is quick and tool-free, utilizing factory mounting holes with no gunsmithing needed. This accessory enhances reload speed and tactical versatility, making it a must-have for home defense and hunting enthusiasts alike.












| ASIN | B07WHN74TW |
| Best Sellers Rank | #34,203 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #27 in Hunting & Shooting Gun Holders |
| Brand Name | Monstrum |
| Closure Type | Open Top |
| Color | Tan |
| Customer Reviews | 4.6 4.6 out of 5 stars (3,920) |
| Manufacturer | Monstrum |
| Material Type | Polymer |
| UPC | 850004377246 |
M**N
Icing on the Cake
Monstrum is the finishing touch! Bird head grip, factory head shield, and now the Monstrum rail and side saddle. NICE! Good price with the $5 discount code and easy installation. This will last for years. I’m a very satisfied customer!
B**.
A must-have for any shotgun
For a home defense shotgun this is a must-have accessory. It enables you to carry extra ammo while also providing a mounting platform for powered optics, such as a red dot. Most shotguns have limited ammo capacity, and you're not going to have time to grab extra shells if you hear a bump in the night. Having those extra shells already mounted to the gun gives you the opportunity to reload, which could be a lifesaver in a hostile encounter. This product surprised me with its quality and price point. It works great, fits great, holds up well under heavy use, and looks awesome to boot. Buy one - you won't be disappointed. It will fit the Mossberg 590 shockwave. Be sure to order the correct version - there are options for 12ga and 20ga. In order to install this product your shotgun must have a drilled & tapped receiver - in other words, little flat-head screws running down the top centerline of the gun. You may consider installing a larger front sight, because this product adds a little extra height to the receiver, and may make it difficult to aim with a standard bead... or just get a red dot and install it on the rail. Also consider using loctite when you install to prevent the screws from loosening under strain from recoil.
S**E
Great ad on to a 590
Works great,Easy install and fit was good.
K**E
Wish it fit my Mossberg 500 ATP
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.
J**O
It's good, not great.
Had a little bit of difficulty getting the correct product sent to me two times in a row where a different product was sent but on the packaging the label was correct so it was being mislabeled at factory or distribution center for some reason. The product is good, but not great for a couple of reasons: 1. This is a two-piece design and it would be much better if it was one piece so that the picatinny rail was not so high off of the shotgun which automatically puts whatever optic you want on your shotgun higher than you truly need it. 2. I got both versions of this six shell side saddle, one for my 20 gauge and one for my 12 gauge. The one for the 20 gauge required me to cut down my foregrip because it was sliding onto my receiver about 2 in and was hitting the side saddle. This particular 20 gauge Model was the pistol grip Persuader model that had the 9-in stock length foregrip which was entirely too long to fit this accessory so I modified it. 3. Personally I think there's too much play in the rail movement for the screw holes. You get offset or misalign the rail in relation to the barrel quite a bit to throw any optic you put on it out of whack. Most Optics only have so much adjustability and one degree out of absolute parallel is still 1 degree which put you way off Target. 4. All six Shell Holders do not hold the shells evenly. The two outside ones are far looser than the four on the inside. That's just annoying. I like the brass facing down so when you flip the gun upside down it's easier for loading but I'm hoping that they don't fall out while shooting I ordered some other parts from this company so I'll see how the quality is on those when I get them. It did come with the correct length screws so that was a plus.
A**R
"WHEN ORDERING MAKE SURE YOU CLICK ON THE 12 GA OR 20 GA MODEL BEFORE COMPLETING THE PURCHASE".
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.
A**E
Good quality
Good quality
F**A
Shell Holder with Picatinny Rail
Product description clearly defined. Good fit.
Trustpilot
2 weeks ago
2 months ago