About the Rare Breed FRT-MR3 Flat Single-Stage

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 the latest evolution in forced-reset trigger technology from Rare Breed. Designed specifically for the HK MR223 and MR556 platform, this flat-faced trigger brings the same reliable, three-position functionality that shooters expect from the FRT line, now optimized for the German-engineered upper and lower receiver geometry.

Overview

Rare Breed engineered the FRT-MR3 to work exclusively with the HK MR223 and MR556 family. Unlike universal triggers that require shims or modifications, this unit is purpose-built to engage the bolt carrier group interface of the HK platform. The three-position selector gives you safe, semi-automatic, and forced-reset operation. The flat trigger shoe provides a consistent finger placement, reducing felt pull variation during rapid strings. This is not a gimmick; it is a mechanical function that resets the trigger forward as the bolt cycles, allowing for a faster follow-up shot while maintaining positive sear engagement. The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is a direct replacement for the factory trigger pack and requires no permanent alteration to the receiver.

Features & Specs

The FRT-MR3 uses a single-stage design with a crisp break and a short, positive reset. The flat trigger shoe reduces over-travel and gives you a more natural pull angle compared to curved triggers. The three-position selector is clearly marked and includes a positive detent at each stop. Below are the key specifications and design details you can expect from this unit.

• Three-position selector: Safe, Semi, and Forced Reset (FRT) mode with mechanical reset via bolt carrier movement.
• Flat trigger shoe with serrated face for reduced slip under rapid fire or wet conditions.
• Drop-in design for HK MR223 and HK MR556 lower receivers; includes all necessary pins and springs.
• Single-stage pull weight approximately 4.5 to 5.5 pounds as tested on factory-spec receivers.
• Constructed from heat-treated steel with a phosphate finish for corrosion resistance and durability.

When installing the FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556, make sure your lower receiver is in spec. Some aftermarket lowers may require minor fitting, but factory HK receivers will accept this trigger without issue. Always verify bolt carrier group compatibility before installation.

Who It's For

This trigger is intended for experienced shooters who own an HK MR223 or MR556 and want to explore forced-reset operation without sacrificing reliability. It appeals to competitive shooters looking for faster split times in practical rifle matches, as well as collectors who want to experience the mechanical innovation of the FRT system in a premium platform. It is also suitable for law enforcement or professional users who train with the HK platform and need a consistent, repeatable trigger pull across all three modes. If you are building a dedicated MR556 upper and want a trigger that keeps up with the rifle's gas system, this is the component you have been searching for. The FRT-MR3 (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is not a training tool for beginners; it is a precision instrument for those who understand the mechanics of their firearm.

Shipping, returns and FFL transfer

• Parts and accessories ship to your door where state and local law allow.
• Shipping is $29.99 per order, free on orders over $999. Orders usually leave within 1–3 business days after payment clears.
• Unused items in original packaging can be returned within 30 days of delivery.

Full terms: shipping and FFL transfers · returns and refunds · FAQ · contact us.

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