FRT-MR3™ (Flat)
The FRT-MR3™ (Flat) is the flat-faced evolution of Rare Breed Triggers’ HK platform forced reset trigger. Everything that made the FRT-MR3™ the definitive upgrade for HK MR223 and MR556 shooters — now with a precision flat-face trigger bow engineered for more consistent, more ergonomic trigger press on every shot.
| Model | FRT-MR3™ (Flat) |
| Type | Single-Stage Forced Reset Trigger |
| Trigger Face | Flat-Face Design |
| Positions | 3 (Safe / Semi-Auto / Forced Reset) |
| Compatible Platforms | HK MR223, HK MR556 |
| Material | Tool-Grade Steel, Precision Machined |
| Finish | Corrosion-Resistant Coating |
| Install | Drop-In, No Modification Required |
| Legal Status | Federally Legal — DOJ Settlement Confirmed |
| Warranty | Manufacturer’s Limited Warranty |
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Product Summary
The FRT-MR3™ (Flat) is the flat-faced evolution of the most advanced forced reset trigger available for the HK MR223 and HK MR556. Engineered by Rare Breed Triggers, it combines three selectable positions — Safe, Semi-Auto, and Forced Reset — with a precision flat-face trigger bow that delivers a more consistent, more ergonomic trigger press with every single shot.
The patented BCG-driven reset mechanism delivers mechanically faster, more consistent reset than any spring-driven trigger. One round per trigger pull. Federally legal — confirmed by the DOJ settlement with Rare Breed Triggers. No modification to your rifle required. Ships direct with full warranty coverage.
HK precision. Flat face. Forced reset. Zero compromise.
What Is the FRT-MR3™ (Flat)?
The FRT-MR3™ (Flat) is the flat-faced variant of Rare Breed Triggers’ purpose-built HK platform forced reset trigger. It delivers the complete FRT-MR3™ feature set — three selectable positions, patented BCG-driven forced reset, tool-grade steel construction, and drop-in compatibility with the HK MR223 and MR556 — with the addition of a flat-face trigger bow engineered for superior ergonomics and press consistency.
The flat-face advantage is well understood by competitive and serious shooters: a flat trigger bow allows the finger to make contact at a more consistent point regardless of exactly where it lands, reducing variation in press direction and improving perceived break quality. When paired with the rapid BCG-driven reset of the FRT-MR3™ system, this ergonomic refinement compounds — giving HK MR-series shooters a trigger that is not only faster, but more repeatable and more controllable under speed.
Like all Rare Breed Triggers products, the FRT-MR3™ (Flat) carries federally confirmed legal status, ships with the manufacturer’s warranty, and is available exclusively at rare-breedtriggers.com — the only authorized source for genuine Rare Breed FRT products.
Flat Face + Forced Reset: Why It Matters for HK Shooters
HK MR-series shooters represent a distinct segment of the firearms market — one defined by an appreciation for precision engineering, exceptional reliability, and premium build quality. The FRT-MR3™ (Flat) was developed to match that standard. The flat-face trigger bow reflects the same attention to ergonomic detail that defines the HK platform itself, while the forced reset mechanism delivers a performance ceiling that no standard trigger upgrade can approach.
For competitive shooters running the HK MR223 or MR556, the combination of flat-face ergonomics and forced reset speed makes the FRT-MR3™ (Flat) the most capable trigger upgrade available for the platform. For range and training use, the three-position design allows the shooter to move seamlessly between standard semi-auto and forced reset mode — adapting to whatever the session demands. Read our platform guides on the blog.
Three Positions. Flat Face. Total Control.
Trigger sear mechanically disconnected. The firearm cannot fire regardless of trigger pressure. Standard safe carry and storage position for all non-firing situations.
Standard single-stage semi-automatic function with the flat-face trigger bow. One round per deliberate pull. Spring-driven reset. Ideal for precision work and deliberate engagement on the HK MR platform.
The patented BCG-driven reset engages. The bolt carrier group physically drives the flat-face trigger forward after each shot — delivering mechanically faster, more consistent reset. One round per trigger pull. Federally legal semi-automatic operation.
The Flat-Face HK Advantage
Promotes consistent finger placement on every pull — reducing press-direction variation and improving break quality. When paired with forced reset speed, the result is a shooting experience that is both faster and more controlled.
Not an AR-15 adaptation — engineered specifically for the HK MR-series trigger group geometry. Every dimension is precise to the HK MR223 and MR556 platform for a clean, reliable fit.
The bolt carrier group mechanically drives the trigger forward during cycling — the patented forced reset mechanism from Rare Breed Triggers, now available for HK MR-series shooters.
Every primary wear surface precision machined from tool-grade steel — built to match the durability standard of the HK platform for thousands of rounds of reliable service.
One round per trigger pull in every position. Confirmed semi-automatic classification by the landmark DOJ settlement with Rare Breed Triggers.
Every FRT-MR3™ (Flat) purchased from Rare Breed Triggers ships with the manufacturer’s limited warranty. Only direct purchases qualify.
Federally Legal. DOJ Confirmed.
The FRT-MR3™ (Flat) fires one round per single function of the trigger in every position. Under the National Firearms Act and Gun Control Act, a machine gun fires more than one round per trigger function. The FRT-MR3™ (Flat) does not meet this definition — confirmed by the DOJ settlement with Rare Breed Triggers.
State laws vary. Always verify your state’s specific regulations before purchasing. Read our full legal guides on the blog.
Frequently Asked Questions
The only difference is the trigger bow geometry. The FRT-MR3™ (Flat) features a flat-faced trigger bow rather than the curved bow of the standard FRT-MR3™. The BCG-driven forced reset mechanism, three-position selector, tool-steel construction, and HK MR223/MR556 compatibility are identical across both variants.
Yes. The FRT-MR3™ (Flat) is a federally legal semi-automatic trigger — one round per trigger pull in every position. Its legal status is confirmed by the DOJ settlement with Rare Breed Triggers. State laws vary — always verify before purchasing. Read our legal breakdown here.
No. The FRT-MR3™ (Flat) is a drop-in assembly designed for the HK MR223 and MR556 trigger group. No machining or permanent modification to your rifle is required.
The only authorized source is rare-breedtriggers.com. Purchasing direct guarantees authenticity, manufacturer warranty, and legal compliance. There are no authorized third-party resellers.
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Order the FRT-MR3™ (Flat) Today
Flat face. Forced reset. Purpose-built for HK. The most advanced trigger upgrade for your MR223 or MR556.
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