Precision Engineering for Superior Control

Built on Mossberg’s proven pump-action platform, the 590 Shockwave features ambidextrous safety, dual extractors, positive steel-to-steel lockup, and twin action bars for smooth, jam-free operation.

Key Specifications

• Gauge: 20
• Capacity: 6
• Chamber: 3″
• Barrel: 14.375″ Heavy-Walled, Matte Blue
• Choke: Cylinder Bore
• Stock: Raptor Grip / Corn Cob Forend with Strap
• Weight: 4.95 lbs
• Overall Length: 26.37″

Why Choose the 590 Shockwave

Engineered for those who demand premium fit and finish, this model combines compact maneuverability with legendary Mossberg durability.

Mossberg 590 Shockwave 20 Gauge Compact Pump Firearm

The Mossberg 590 Shockwave 20 Gauge is a compact pump-action firearm built for close-range security work. It pairs a short heavy-walled barrel with Mossberg’s proven 590 action. In addition, the Raptor bird’s-head grip keeps overall length short without a shoulder stock. Consequently, the platform stays easy to move through tight rooms, hallways, and vehicle interiors. Furthermore, 20 gauge recoil is milder than a comparable 12 gauge Shockwave. Therefore, more shooters can run the gun with better control.

Overview

This model is Mossberg SKU 50657. It is chambered for 20 gauge shells and accepts 2-3/4 inch and 3 inch loads. Moreover, the official capacity is 5+1. The barrel measures 14.375 inches and uses a cylinder bore. Additionally, overall length is 26.37 inches. Empty weight is 4.95 pounds. As a result, the firearm stays light in the hands during long holds. The receiver is drilled and tapped. Meanwhile, the magazine tube uses a clean-out cap for faster service. The finish is matte blue on the barrel. The furniture is black synthetic. Specifically, that furniture is the Raptor grip plus a corn-cob forend with strap.

The action uses dual extractors, twin action bars, steel-to-steel lockup, and an anti-jam elevator. In addition, the tang safety is ambidextrous. Therefore, left-handed and right-handed users can reach it without changing grip. The front sight is a simple bead. Subsequently, the sight picture stays fast at home-defense distances. However, this is still a short-range tool. Pattern and recoil management matter more than long-range precision.

Key Features

The defining feature is the Shockwave bird’s-head grip. It is shaped to give a firm hold and reduce felt recoil. Additionally, the strapped corn-cob forend keeps the support hand behind the muzzle during a pump stroke. That strap is not cosmetic. It is a control device. Moreover, the heavy-walled barrel adds stiffness in a short package. The clean-out magazine tube simplifies inspection after range use. Furthermore, the drilled and tapped receiver supports optics or a laser saddle if you add one later. Besides those points, the 590 platform already has a long service record in security roles. Consequently, the Shockwave version keeps that same mechanical core in a shorter envelope.

Handling And Control Notes

Control is different from a stocked shotgun. You do not shoulder this firearm. Instead, you drive it from the grip and forend. Therefore, stance, wrist alignment, and a locked support hand matter. In particular, the strap helps keep the lead hand in place under recoil. Also, 20 gauge loads reduce muzzle rise compared with 12 gauge Shockwave models. As a result, follow-up pumps are easier for many shooters.

Specifications List

• Manufacturer: O.F. Mossberg & Sons
• Model: 590 Shockwave
• SKU: 50657
• UPC: 015813506571
• Gauge: 20 Gauge
• Action: Pump-action
• Chamber: 3 inch (also accepts 2-3/4 inch)
• Capacity: 5+1
• Barrel length: 14.375 inches
• Barrel type: Heavy-walled
• Barrel finish: Matte blue
• Choke: Cylinder bore
• Overall length: 26.37 inches
• Weight: 4.95 lbs
• Sights: Front bead
• Stock / grip: Raptor bird’s-head grip
• Forend: Corn-cob with strap
• Safety: Ambidextrous tang safety
• Receiver: Drilled and tapped
• Magazine: Tubular with clean-out cap
• Intended use category: Security

Use Cases

This firearm is built for compact security work. It is not a field-hunting gun with a long barrel and interchangeable chokes. Instead, it is meant for short distances and fast handling. Home interiors, hallways, and vehicle storage are the usual roles. Additionally, the lighter 20 gauge payload helps recoil-sensitive shooters stay on target. However, you still need patterned defensive loads. Buckshot choice changes pattern width quickly in a cylinder-bore 14-inch barrel. Therefore, confirm your load at realistic room distances.

Home Defense In Tight Spaces

In a doorway or hallway, length is the first constraint. The 26.37-inch overall length helps here. Moreover, the bird’s-head grip avoids the bulk of a full buttstock. Consequently, muzzle tracking around corners is simpler. Still, training is required. A short pump firearm rewards a consistent pump stroke and a stable two-hand hold. In addition, keep the support hand on the strapped forend at all times. That habit protects the lead hand and keeps the action cycling cleanly.

Comparative Product Analysis

Compared with the 12 gauge 590 Shockwave, this 20 gauge model is lighter and softer to shoot. The 12 gauge version hits harder with more common duty buckshot. However, the 20 gauge version is easier for smaller-framed shooters and longer practice sessions. In contrast with the .410 Shockwave, the 20 gauge offers a larger payload and more defensive load options. The .410 stays even lighter. Yet it also throws a smaller pattern with fewer pellets.

The closest rival is the Remington 870 TAC-14 family, including 20 gauge TAC-20 style guns. Both use a short barrel and a bird’s-head grip. Mossberg’s advantage is the familiar 590 action, ambidextrous tang safety, and clean-out magazine tube. Remington’s advantage is the huge 870 aftermarket. Similarly, some shooters compare this gun with 18.5-inch stocked 20 gauge pumps. Those stocked guns are easier to shoot from the shoulder. Nevertheless, they are longer and less handy in cramped rooms. This Shockwave trades shoulder purchase for compact length. Therefore, pick the layout that matches the space you actually need to cover.

Regulatory

BATFE has classified the standard 590 Shockwave configuration as a firearm, not an NFA short-barreled shotgun, when it ships with the bird’s-head grip and an overall length over 26 inches. As a result, a federal tax stamp is not required for that factory layout. However, this is still a firearm. An FFL transfer is required. Moreover, adding a shoulder stock to a 14.375-inch barrel can create an NFA short-barreled shotgun. Do not alter the configuration without checking current federal and state law.

State rules vary. Some jurisdictions restrict pistol-grip firearms, overall length, or magazine capacity. California, New York, and Massachusetts are commonly cited as restricted markets for this style of firearm. Consequently, confirm legality with your receiving FFL before transfer. Additionally, local ordinances can be stricter than federal rules. This description is product information, not legal advice. Always verify current ATF and state requirements before purchase or modification.