Description
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 from Rare Breed is a direct replacement upgrade for your HK-pattern semi-automatic rifle. Engineered to the same tolerances as the original FRT-15 platform, this three-position trigger provides a mechanical forced-reset function that returns the trigger forward immediately after each shot. Designed exclusively for the HK MR223 and HK MR556 lower receivers, this unit installs without modification to the host firearm. The flat trigger shoe offers a consistent pull surface, reducing finger slip during rapid strings of fire. Each unit is machined from billet steel and finished with a corrosion-resistant coating. This is a single-stage trigger with a factory-set pull weight that does not require adjustment.
Overview
The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 operates through three distinct selector positions: Safe, Semi-Automatic, and Forced Reset. In the forced reset position, the trigger mechanism mechanically resets the trigger forward after each round, requiring the shooter to release and reapply pressure for the next shot. This design is not a binary trigger or a full-automatic conversion device. It is a mechanical trigger system that relies on shooter input to cycle. Rare Breed manufactures this trigger in the United States using CNC-machined components. The flat shoe geometry allows for a lower bore axis finger placement, which can aid in recoil management. This product is intended for use in legal semi-automatic firearms only.
Features & Specs
- Precision-machined billet steel construction with MIL-SPEC phosphate finish; drop-in compatible with HK MR223 and HK MR556 lower receivers without permanent modification.
- Three-position selector with positive detent engagement: Safe, Semi (standard semi-automatic), and FRT (forced reset mode).
- Flat trigger shoe design with a smooth, consistent face; single-stage pull with a factory-set break weight of approximately 6-7 pounds.
The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 includes all necessary pins and springs for installation. The trigger housing is a standard AR-15 pattern that fits the HK MR223 and MR556 pocket without modification. The forced reset function is mechanically actuated by the bolt carrier group, not by gas or electronic systems. This trigger is compatible with standard HK MR223 and MR556 bolt carrier groups. Always verify that your firearm is in good working order before installation.
Who It’s For
- HK MR223 and MR556 owners who want a precision single-stage trigger with an additional forced reset capability for competitive shooting or training.
- Shooters who prefer a flat trigger shoe for consistent finger placement and reduced over-travel sensitivity.
- Individuals who require a drop-in trigger system that does not require gunsmith fitting and that maintains the original safety selector positions.
This trigger is not for users who want a standard two-stage trigger, nor is it for those unfamiliar with forced reset mechanics. The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 requires the shooter to understand and practice the forced reset technique. It is a purpose-built component for experienced shooters who want a mechanical alternative to standard semi-automatic triggers.
Shipping & FFL
- This product is a firearm component and will ship directly to your address. No Federal Firearms License (FFL) is required for purchase or delivery.
- You must be at least 18 years of age to purchase and 21 years of age if your state law requires it. By purchasing, you certify that you are legally eligible to own firearm parts.
- Check your local, state, and federal laws before ordering. The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is legal in most states, but some jurisdictions have restrictions on forced reset triggers. It is the buyer’s responsibility to ensure compliance with all applicable laws. We will not ship to states or localities where this product is prohibited.
All orders are processed within one business day. Standard shipping is via UPS Ground. Expedited options are available at checkout. No international shipping.

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