FRT-RD3™ (SEF)

Two-Stage 3-Position Forced Reset Trigger for HK MP5, MP5K, SP5 & SP5K Platforms

Upgrade your HK roller-delayed platform with the official Rare Breed Triggers FRT-RD3™ (SEF) — a premium drop-in, duty-grade forced reset trigger engineered specifically for HK MP5, MP5K, SP5, and SP5K firearms.

Manufactured and assembled in the USA, the FRT-RD3™ (SEF) delivers advanced trigger performance, precision engineering, and rugged reliability tailored for HK SEF-style grip frame configurations.

Featuring a 3-position selector system with Safe, Semi-Automatic, and Forced Reset Trigger (FRT®) modes, the FRT-RD3™ (SEF) includes an SEF-style safety selector designed for traditional HK grip frame compatibility.

Performance Designed for HK Roller-Delayed Platforms

The FRT-RD3™ (SEF) is engineered to enhance shooting performance through an advanced forced reset mechanism that improves trigger reset speed, consistency, and control.

The system mechanically resets the trigger after each shot, enabling faster follow-up shots while maintaining full shooter control and predictable operation.

Each trigger pull is designed to fire one round, ensuring a controlled shooting experience suitable for competition, training, and range use.

Key Features

3-Position SEF Selector System

The FRT-RD3™ (SEF) features a traditional HK SEF-style selector system designed for classic grip frame layouts.

Selectable modes include:

• Safe Mode (S – Sicher)
• Semi-Automatic Mode (E – Einzelfeuer)
• Forced Reset Trigger (FRT®) Mode

The single-sided selector design is consistent with traditional HK SEF configurations.

Drop-In Installation

The FRT-RD3™ (SEF) is engineered for straightforward installation in compatible HK SEF-style grip frames.

Its plug-and-play design allows for a streamlined setup experience without requiring firearm modification in compatible platforms.

Two-Stage Trigger Performance

The FRT-RD3™ (SEF) is designed from the ground up as a dedicated HK roller-delayed trigger system, delivering a refined two-stage trigger feel.

Key performance characteristics include:

• Smooth first-stage take-up
• Crisp second-stage break
• Consistent reset behavior
• Improved trigger control and repeatability

This geometry ensures proper timing and reliable operation within HK roller-delayed systems.

Built for Durability

The FRT-RD3™ (SEF) is manufactured using premium-grade materials designed for long-term performance and reliability:

• 7075 anodized aluminum
• Heat-treated 4140 steel components

This rugged construction ensures durability under demanding use conditions.

HK MP5 / SP5 Platform Compatibility

The FRT-RD3™ (SEF) is specifically engineered for HK roller-delayed platforms, including:

• HK MP5
• HK MP5K
• HK SP5
• HK SP5K

It is designed to operate with the factory semi-automatic bolt carrier group used in these platforms.

Compatible configurations include models with factory full-auto carrier denial blocks in the receiver, requiring no firearm modification for installation.

For added flexibility, the FRT-RD3™ (SEF) is also compatible with full-auto bolt carrier groups, though one is not required for operation.

HK SEF Grip Frame Compatibility

The FRT-RD3™ (SEF) is designed for traditional HK SEF-style grip frames, identified by:

• S (Sicher – Safe)
• E (Einzelfeuer – Semi-Automatic)
• F (Feuerstoß – Full Auto marking)
• Single-sided left-side selector lever
• Directional indicator “tail” aligned with selector markings

This ensures proper alignment with classic HK SEF control layouts.

Speed, Precision & Control

The FRT-RD3™ (SEF) is engineered for shooters seeking improved performance from HK roller-delayed platforms.

By mechanically resetting the trigger after each shot and preventing trigger engagement until the bolt carrier group returns to battery, the system enables a faster, more consistent shooting rhythm while maintaining full control over each individual shot.

The forced reset mechanism ensures the trigger returns to the ready position after each round, requiring a deliberate pull for every shot.

Why Choose the FRT-RD3™ (SEF)?

The FRT-RD3™ (SEF) is the ultimate trigger upgrade for HK MP5, MP5K, SP5, and SP5K platforms.

Combining HK-specific engineering, two-stage trigger refinement, durable construction, and forced reset technology, it delivers a premium performance experience for competition, training, and range applications.

Unlock the full potential of your HK roller-delayed firearm with the FRT-RD3™ (SEF).

Manufactured & Assembled in the USA