FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556

Precision-engineered for the HK MR223 and HK MR556 platform, the FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger from Rare Breed represents a significant advancement in trigger system design. This unit is purpose-built for shooters who demand a consistent, repeatable trigger reset under high-speed operation. The FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 integrates a unique three-position selector that provides a safe, a semi-automatic, and a forced-reset position, enabling a controlled cyclic rate without modifying the firearm’s internal safety architecture.

Overview

The FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is a direct drop-in replacement component that leverages the existing lower receiver geometry of the HK MR223 and MR556. Rare Breed has engineered this trigger to function exclusively within the mechanical limits of the forced reset system, where the trigger is physically returned forward by the bolt carrier group after each shot. This design eliminates the need for binary or burst pack modifications while maintaining a single-stage pull weight that is optimized for rapid follow-up shots. The flat trigger shoe offers a consistent finger placement surface, reducing variability during high-round-count sessions.

Features & Specs

Every aspect of the FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 has been machined to precise tolerances. The system utilizes a hardened steel sear and hammer set, paired with a stainless steel trigger bow that resists wear under sustained use. The three-position selector is clearly indexed, allowing immediate visual and tactile confirmation of mode selection. Below are the key specifications and included features:

• Three-position selector: Safe, Semi-Automatic, and Forced Reset (FRT) mode. The forced reset position requires the bolt carrier to cycle fully before the trigger can be pulled again, creating a distinct mechanical boundary for each shot.
• Flat trigger shoe geometry with integrated over-travel stop. The shoe profile reduces trigger finger movement and provides a consistent 90-degree perpendicular pull angle relative to the receiver.
• Drop-in design for the HK MR223 and MR556 lower receiver. No permanent modifications, drilling, or fitting required. Installation uses factory hammer and trigger pins.

• Material composition: 4140 steel hammer and sear, 17-4 PH stainless steel trigger shoe, and hardened steel selector. All components are finished with a matte black nitride coating for corrosion resistance.
• Trigger pull weight: Single-stage, factory set at 4.5 pounds +/- 0.5 pounds. No user-adjustable pull weight to maintain consistent mechanical timing.
• Compatibility: Specifically designed for the HK MR223 and HK MR556 bolt carrier group and upper receiver assembly. Not compatible with AR-15 or DI-style systems.

• Includes: Complete trigger assembly, three-position selector lever, detent spring, and installation instructions. No additional parts required.
• Warranty: Backed by Rare Breed’s standard manufacturer warranty against defects in materials and workmanship. Warranty does not cover misuse or modification.
• Testing: Each unit is function-checked at the factory to ensure proper forced-reset operation across the full cyclic range of the HK MR223 and MR556.

Who It’s For

This trigger is intended for experienced shooters who own an HK MR223 or HK MR556 and are familiar with the mechanical requirements of forced reset systems. The FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is suited for competitive shooters, firearms instructors, and enthusiasts who train with high-volume, controlled-pair shooting drills. It is not a speed-firing device but rather a system that enforces a mechanical reset discipline. Users must understand that the forced reset function relies entirely on the bolt carrier returning to battery; any malfunction or short-stroke condition will interrupt the trigger cycle. This product is not designed for novice shooters or for use in firearms that have been modified outside of factory specifications.

Shipping & FFL

This product ships directly to your residential or business address within Ohio. No FFL transfer is required for this item as it is a trigger component and does not constitute a firearm receiver. However, all applicable federal, state, and local laws regarding firearm parts installation and possession apply. By purchasing the FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556, you acknowledge that you are responsible for verifying compliance with all local ordinances and regulations in your jurisdiction. Rare Breed and the retailer assume no liability for improper installation or use. Standard shipping rates apply; expedited options are available at checkout.