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

The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is a precision-engineered drop-in trigger system designed exclusively for the HK MR223 and HK MR556 platform. Manufactured by Rare Breed, this forced reset trigger (FRT) leverages a three-position selector to provide shooters with a distinct mechanical cycling method. Unlike binary or burst triggers, the FRT-MR3 utilizes the forward motion of the bolt carrier to reset the trigger shoe, enabling a rapid, controlled firing sequence that demands proper trigger discipline. This product is built for users who require a flat, single-stage interface with a forced reset mechanism that maintains the firearm’s integrity while increasing cyclic performance.

Overview

The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is a dedicated upgrade for the HK MR223 and MR556 rifles, offering a three-position safety selector (Safe / Semi-Automatic / Forced Reset). The forced reset position forces the trigger shoe to reset forward after each shot, requiring the shooter to release and re-pull the trigger for each subsequent discharge. This system does not alter the firearm’s classification under federal law, as each pull of the trigger produces only one round. The flat trigger shoe provides a consistent, repeatable pull surface, reducing finger fatigue during extended range sessions. Rare Breed has engineered this trigger to fit the HK MR223 and MR556 lower receiver without modification, utilizing a proprietary cassette design that isolates the forced reset components from the hammer and disconnector.

Features & Specs

• Mechanical Operation: The FRT-MR3 employs a forced reset mechanism that uses bolt carrier travel to return the trigger shoe to the forward position. In the third selector position, the trigger must be fully released and depressed for each shot, ensuring compliance with semi-automatic definitions while enabling elevated shot-to-shot speed.
• Flat Trigger Shoe: A wide, flat trigger shoe with a smooth face reduces side-to-side finger movement and provides a consistent contact point. The shoe is CNC-machined from 7075-T6 aluminum with a hard-coat anodized finish for durability in high-round-count applications.
• 3-Position Selector: The selector switch includes three clearly indexed positions: Safe (blocked), Semi-Automatic (standard single-action fire), and Forced Reset (mechanically assisted reset). The selector is ambidextrous and compatible with standard HK MR223/MR556 lower receiver detents.
• Drop-In Design: The trigger ships as a pre-assembled cassette unit requiring no permanent modification to the lower receiver. Installation involves removing the factory trigger group, inserting the FRT-MR3 unit, and securing it with the included pins and springs. No filing, fitting, or gunsmithing is necessary.
• Materials & Finish: Internal components are constructed from heat-treated tool steel with a nickel-Teflon coating for reduced friction. The hammer is case-hardened to withstand the HK platform’s high-pressure bolt carrier impact. The cassette housing is 6061-T6 aluminum with Type III hard coat anodizing.
• Compatibility: Specifically engineered for the HK MR223 (imported variants) and HK MR556 (U.S. commercial model). Does not fit AR-15, AR-10, or other HK-pattern rifles without significant modification. Confirmed to function with factory HK trigger pins and safety selectors.

Who It’s For

This trigger is intended for experienced shooters who own an HK MR223 or HK MR556 and seek a forced reset trigger that maintains the platform’s reliability. It is suitable for competitive shooters in divisions that permit forced reset triggers, training instructors who require high-volume repetition drills, and collectors who want a purpose-built trigger for their HK-pattern rifle. The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is not recommended for first-time firearm owners or those unfamiliar with forced reset mechanics, as the trigger requires deliberate finger control to avoid unintentional discharges. Users should be proficient in safe firearm handling and understand the mechanical function of forced reset triggers before installation. This product is designed for law-abiding civilians and commercial ranges; it is not authorized for use by any federal, state, or local law enforcement agency under standard procurement.

Shipping & FFL

This trigger is classified as a firearm component and is not a firearm frame or receiver. It can be shipped directly to your residential or business address within the United States. No Federal Firearms License (FFL) transfer is required for purchase or delivery. You must be at least 18 years of age to purchase this product. Check your state and local laws regarding the possession and use of forced reset triggers before ordering. Some jurisdictions have enacted restrictions on devices that increase a firearm’s rate of fire. It is your responsibility to verify that this product is legal in your location. Rare Breed and this retailer assume no liability for non-compliance with local ordinances. Shipping is via UPS Ground or FedEx Home Delivery with adult signature required at delivery. Typical transit time is 3–5 business days after order processing. International shipping is not available for this item.