ERGO MOSSBERG 12-GAUGE 500/590 RAIL (SHOCKWAVE) Type "B" - SKU: 4872 - UPC: 874748006569
Product Description
The ERGO Mossberg 12-Gauge 500/590 M-LOK Forend Rail Type "B" (4872) is a precision-engineered aluminum forend replacement designed specifically for Mossberg 12-gauge pump-action shotguns, including the compact Mossberg 590 Shockwave series. Built to replace restrictive factory polymer forends, this lightweight M-LOK handguard provides a modern, modular interface for staging tactical lights, foregrips, handstops, and sling mounts.
Precision CNC-machined from 6061-T6 aircraft-grade aluminum and finished in a matte black hardcoat anodizing, the ERGO Type "B" rail features M-LOK attachment slots on the sides and bottom. The ergonomic, slim profile maintains smooth forend movement while resisting heat buildup during rapid firing schedules.
The Type "B" designation is specifically tailored for Mossberg 12-gauge action slide assemblies utilizing the standard 6-3/4" to 7-3/4" action slide tube lengths. It installs securely onto the action slide tube, providing rock-solid mounting without adding unnecessary bulk to your shotgun build.
*Armorer Bench Notes & Real-World Staging Guidance:
Fitment Matrix: Fits Mossberg 500 / 590 / 590 Shockwave 12-Gauge models requiring a Type "B" forend length (works with standard removable 6-3/4" to 7-3/4" action slide tube assemblies). (Will NOT fit Mossberg Maverick 88 models with pin-attached action bars unless upgraded to a 500/590 action tube, nor models with fixed 1-piece pinned forends).
- Verify host shotgun is completely clear, magazine tube empty, and chamber visually and physically confirmed empty.
- Unscrew magazine tube cap, pull barrel forward and remove from receiver.
- Use a castle nut spanner tool to unscrew and remove the action slide tube nut from the front of the factory forend.
- Slide original forend off the steel action slide tube assembly and clean tube surface threads.
- Slide ERGO 4872 rail onto action slide tube, rethread the factory retaining nut, torque securely, and reinstall barrel and tube cap.
Key Features
- Modular M-LOK Compatibility: M-LOK slots situated at 3, 6, and 9 o'clock positions allow mounting of weapon lights, grips, and sling points.
- Type "B" Action Tube Architecture: Designed specifically to fit standard Mossberg 12-gauge action slide assemblies.
- 6061-T6 Billet Aluminum Construction: Offers maximum structural rigidity under heavy 12-gauge recoil impulse.
- Mil-Spec Type III Hardcoat Anodized: Tough, non-reflective black finish protects against surface scratch abrasion and barrel heat.
- Ergonomic Slim Contour: Reduces overall forend bulk while retaining positive purchase during rapid cycle racking.
- Direct Drop-In Upgrade: Replaces factory plastic forend using the original action slide tube retaining nut.
Product Specifications
- Brand: ERGO Grips
- MPN: 4872
- UPC: 874748006569
- Platform Compatibility: Mossberg 500 / 590 / 590 Shockwave 12-Gauge (Type B Assembly)
- Attachment Interface: Modular M-LOK Slots
- Material: 6061-T6 Billet Aluminum
- Finish/Color: Matte Black Hardcoat Anodized
- Included Accessories: 3x M-LOK Compatible Rail Covers Included
