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

If you run an HK MR223 or MR556, you know the platform demands precision and reliability. The FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is a direct-fit upgrade engineered by Rare Breed to match the operating characteristics of these rifles. This is not a generic AR-15 trigger shoehorned into an HK lower. It is a purpose-built forced reset trigger designed around the HK hammer geometry and bolt carrier profile. The flat face gives you a consistent finger placement every time, and the three-position selector provides distinct modes: safe, semi-automatic, and forced reset. The forced reset function uses the bolt carrier’s forward movement to mechanically reset the trigger, allowing for rapid, controlled follow-up shots while maintaining manual control over each trigger press. No modification to your lower receiver is required, and installation follows standard HK trigger replacement procedures. This is the same engineering philosophy Rare Breed applied to their FRT-15, now refined specifically for the HK MR223 and MR556 platform.

Overview

The FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is a drop-in trigger assembly that replaces your factory HK trigger pack. It uses a flat, single-stage shoe with a crisp break and a short, tactile reset. The forced reset mechanism engages only when the bolt carrier drives the hammer back, resetting the trigger sear contact. In practice, this means your trigger finger must release fully between shots for the forced reset to occur. The trigger does not automatically cycle the firearm. It simply resets the trigger geometry faster than a standard trigger, enabling you to maintain a consistent sight picture during rapid strings of fire. The housing is machined from billet aluminum with a hard-coat anodized finish, and all internal components are heat-treated tool steel. It is a direct replacement for the MR223 and MR556 factory trigger group with no permanent modifications to your firearm.

Features & Specs

• Flat single-stage trigger shoe with a smooth, non-slip face for consistent finger placement; single-stage break with no take-up or creep; forced reset function engages on bolt carrier return
• Three-position selector: Safe, Semi-automatic, Forced Reset; selector stops are clearly defined with positive detent engagement; safe position blocks hammer and trigger movement
• Constructed from billet aluminum housing with Type III hard-coat anodizing; all internal steel components are heat-treated and QPQ coated for corrosion resistance and reduced friction

The FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 uses the same Rare Breed patented forced reset mechanism found in their FRT-15 line. The hammer profile is optimized for HK bolt carriers to ensure reliable primer strikes and consistent hammer follow. The trigger pull weight is set at the factory and is not user-adjustable. The flat shoe reduces the distance between the trigger face and the grip, which can be beneficial for shooters with shorter fingers or those who prefer a more vertical trigger finger angle. The trigger housing includes integral trigger and hammer pin pockets that align with the HK lower receiver geometry without the need for anti-walk pins.

Who It’s For

This trigger is for HK MR223 and MR556 owners who want a single-stage trigger with a forced reset function without modifying their firearm. It is suitable for competitive shooters in divisions that allow forced reset triggers, as well as recreational shooters who train for rapid, controlled follow-up shots. The flat shoe is preferred by shooters who run a high grip or use a thumb-forward grip style, as it reduces trigger finger drag. It is also for HK owners who have been frustrated by aftermarket triggers that do not fit the MR223 or MR556 lower receiver correctly. Because this trigger is designed specifically for the MR223 and MR556, it eliminates the fitment issues common with universal AR-15 triggers in these platforms. If you run a suppressed MR556 or MR223, the forced reset function pairs well with the increased bolt carrier velocity from suppressor backpressure, but the trigger will function reliably across all gas settings and ammunition types.

Shipping & FFL

This product is a firearm component and is not classified as a firearm by the ATF. It can be shipped directly to your residence or business. No Federal Firearms License (FFL) is required for this transaction. However, you must be 18 years of age or older to purchase, and you must comply with all applicable state and local laws regarding the ownership and installation of aftermarket trigger components. Some states and localities have restrictions on forced reset triggers. It is your responsibility to verify that the FRT-MR3™ (Flat) Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556 is legal in your jurisdiction before placing an order. We do not ship to states or municipalities where this product is prohibited. By purchasing, you certify that you are legally allowed to possess and install this component. If you have questions about your local laws, consult a legal professional familiar with firearms regulations in your area. Standard shipping rates apply, and we ship within one business day of cleared payment.