---
product_id: 161561204
title: "Side Saddle Shell Holder with Picatinny Rail Mount for Mossberg 500/590/Shockwave Series Shotguns"
brand: "monstrum"
price: "NT$2816"
currency: TWD
in_stock: true
reviews_count: 8
category: "Monstrum"
url: https://www.desertcart.tw/products/161561204-side-saddle-shell-holder-with-picatinny-rail-mount-for-mossberg
store_origin: TW
region: Taiwan
---

# Picatinny rail for optics Fits Mossberg 500/590/Shockwave No gunsmithing needed install Side Saddle Shell Holder with Picatinny Rail Mount for Mossberg 500/590/Shockwave Series Shotguns

**Brand:** monstrum
**Price:** NT$2816
**Availability:** ✅ In Stock

## Summary

> 🔫 Reload faster, aim sharper, dominate smarter.

## Quick Answers

- **What is this?** Side Saddle Shell Holder with Picatinny Rail Mount for Mossberg 500/590/Shockwave Series Shotguns by monstrum
- **How much does it cost?** NT$2816 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.tw](https://www.desertcart.tw/products/161561204-side-saddle-shell-holder-with-picatinny-rail-mount-for-mossberg)

## Best For

- monstrum enthusiasts

## Why This Product

- Trusted monstrum brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Durable Aluminum Build:** Lightweight yet rugged aluminum construction ensures long-lasting performance under heavy use.
- • **Tool-Free Installation:** Installs easily with included set screws using factory mounting holes—no gunsmithing required.
- • **Ready for Rapid Reloads:** Securely holds 6 shells (12ga) or 7 shells (20ga) for instant access when seconds count.
- • **Tailored Fit for Mossberg:** Specifically engineered for Mossberg 500, 590, and Shockwave series for a seamless, secure fit.
- • **Optics-Optimized Rail Mount:** Integrated Picatinny/Weaver rail lets you mount red dots or scopes for precision targeting.

## Overview

The Monstrum Side Saddle Shell Holder is a precision-engineered aluminum accessory designed exclusively for Mossberg 500, 590, and Shockwave shotguns. It securely holds up to six 12-gauge or seven 20-gauge shells, while its integrated Picatinny rail enables mounting of optics like red dots or scopes. Installation is straightforward with included set screws, requiring no gunsmithing, making it an essential upgrade for professionals and enthusiasts seeking rapid reload capability and enhanced targeting.

## Description

desertcart.com : Monstrum Side Saddle Shell Holder with Picatinny Rail Mount for Mossberg 500/590/Shockwave Series Shotguns | 12 Gauge : Sports & Outdoors

Review: 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.
Review: Well worth the money - Great holder! Easy install. Firm grip on shells. Looks great.

## Features

- 100% Weave
- Built for use with Mossberg 500, 590, and Shockwave Series shotgun models
- Not compatible with Mossberg 500 Bantam, Mossberg 500 Combo, Mossberg 500 Flex Models or models where the pump action extends past the receiver when pumped. See attached infographic before purchasing. Pre-1997 Mossberg shotguns were manufactured with a different mounting hole pattern and will require 6x48TPI screws (not included).
- Shell holder available in two sizes - 12 gauge saddle accomodating up to six 12 gauge shells and 20 gauge saddle accomodating up to seven 20 gauge shells
- Rail mount allows for the mounting of Picatinny or Weaver standard scopes, red dots, or other optics
- Installs via included set screws into the Mossberg factory mounting holes with no additional gunsmithing required

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B07WHN74TW |
| Best Sellers Rank | #42,253 in Sports & Outdoors ( See Top 100 in Sports & Outdoors ) #31 in Hunting & Shooting Gun Holders |
| Brand | Monstrum |
| Brand Name | Monstrum |
| Closure Type | Open Top |
| Color | Tan |
| Customer Reviews | 4.6 out of 5 stars 3,748 Reviews |
| Manufacturer | Monstrum |
| Manufacturer Part Number | Z83 |
| Material | Aluminum |
| Material Type | Aluminum |
| Number of Compartments | 1 |
| Number of Items | 1 |
| UPC | 850004377246 |

## Product Details

- **Brand:** Monstrum
- **Closure Type:** Open Top
- **Color:** Tan
- **Manufacturer:** Monstrum
- **Material:** Aluminum

## Images

![Side Saddle Shell Holder with Picatinny Rail Mount for Mossberg 500/590/Shockwave Series Shotguns - Image 1](https://m.media-amazon.com/images/I/619vpJD7W5L.jpg)

## Available Options

This product comes in different **Style** options.

## Questions & Answers

**Q: Will this mount to the mossberg maverick 88 12g?**
A: You can drill and tap it yourself.  It will fit if you are willing and able to do this correctly.  It is a bit of a pain, but it is a great way to save $250 over moving up to a 500 or 590 just for the holes.   You can buy a drill press, still have money left over, and get an optic mounted on your shotty.

The 88 is fantastic for the money, except for the lack for 4 holes atop the receiver.  :(

**Q: I have a crimson trace on my Mossberg 590, will this be too much to fit on there?**
A: I ordered this for use with my Shockwave with crimson trace. The crimson trace changes the profile of the receiver and the mount did not sit flush when installed.  I opted for the GG&G side saddle designed for the shock wave. More expensive but better quality. 
When installed the top rail and side saddle was canted to the right and also it sat way too high above bore.

**Q: Is this good for 590 shockwave 20 gauge?**
A: I have a 590 shockwave 12 gauge and fit and works great

**Q: Will this fit a mossberg 940?**
A: It has predrilled holes that makes it compatible with almost all shotguns, so yes.

## Customer Reviews

### ⭐⭐⭐⭐⭐ A must-have for any shotgun
*by B***. on September 19, 2021*

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.

### ⭐⭐⭐⭐⭐ Well worth the money
*by O***N on May 5, 2026*

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

### ⭐⭐⭐⭐⭐ BEST ATTACHMENT IVE BOUGHT IN A LONG TIME
*by G***T on April 14, 2026*

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.

## Frequently Bought Together

- Monstrum Side Saddle Shell Holder for Mossberg 500/590/Shockwave Series Shotguns
- ZOEKIM Tactical Grip Glove for Mossberg 590 500 Shockwave Accessories & Remington Tac-14 Rubber Grip Sleeve
- XXTACMM Enhanced Slide Safety for Mossberg 500 590 835 930 Shockwave Accessories Aluminum 5 Color Option

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**Shop now:** [https://www.desertcart.tw/products/161561204-side-saddle-shell-holder-with-picatinny-rail-mount-for-mossberg](https://www.desertcart.tw/products/161561204-side-saddle-shell-holder-with-picatinny-rail-mount-for-mossberg)

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*Product available on Desertcart Taiwan*
*Store origin: TW*
*Last updated: 2026-08-10*