Polymer80Outlet is a Duluth, MN-based retailer specializing in high-quality firearm components and accessories. The FRT-MR3 (FLAT) is a single-stage, 3-position forced reset trigger designed specifically for the HK MR223 and HK MR556 platforms. Known for its precision engineering and reliable performance, this trigger is available now for $603.75.
Reviewed by Travis Holden, Technical Director at Polymer80Outlet. 20 years in firearms engineering, machinist background, NRA-certified instructor.
Last updated: May 2026
| Product Type | Forced Reset Trigger |
|---|---|
| Material | High-Grade Steel |
| Manufacturing | CNC Machined |
| Finish | Nitride Coated |
| Hardness/Quality | 58-60 HRC |
| Compatibility | HK MR223, HK MR556 |
| Installation/Usage | Drop-In Ready |
| Weight | 2.5 oz |
| Dimensions | 1.5″ x 0.5″ x 0.25″ |
| Country of Origin | USA |
| Condition | New |
| SKU | FRT-MR3-FLAT |
Key Features
- Single-stage, 3-position forced reset mechanism
- Includes anti-walk pins and screws for secure installation
- Comes with A1 and A4 selector drums for customization
- CNC machined from high-grade steel for durability
- Nitride coated finish for corrosion resistance
Who It’s For
Buy it if:
- You own an HK MR223 or HK MR556 and want a reliable forced reset trigger
- You value precision engineering and durability in firearm components
- You prefer drop-in ready triggers for easy installation
Skip it if:
- You’re looking for a budget option (check out our Triggers for alternatives)
- You don’t own compatible HK platforms
Pros & Cons
✅ Precision CNC machining ensures consistent performance
✅ Nitride coating provides excellent corrosion resistance
✅ Drop-in ready design simplifies installation
✅ Includes anti-walk pins and selector drums for customization
❌ Higher price point compared to basic triggers
❌ Limited compatibility with HK MR223 and HK MR556 platforms
Comparison
| Feature | FRT-MR3 (FLAT) | Cheap Import | Premium Brand |
|---|---|---|---|
| Material | High-Grade Steel | Lower-Grade Steel | High-Grade Steel |
| Quality | CNC Machined | Cast | CNC Machined |
| Compatibility | HK MR223, HK MR556 | Multiple Platforms | Multiple Platforms |
| Shipping | Same-Day | 1-2 Weeks | 1 Week |
| Lifespan/Durability | High | Medium | High |
| Price | $603.75 | $60-80 | $250+ |
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FAQ
What platforms is the FRT-MR3 compatible with?
The FRT-MR3 is compatible with the HK MR223 and HK MR556 platforms.
Is the FRT-MR3 drop-in ready?
Yes, the FRT-MR3 is designed for easy drop-in installation.
What’s included in the package?
The package includes 1 x FRT-MR3 Trigger, 2 x Anti-Walk Pins, 4 x Anti-Walk Pin Screws, 1 x A1 Selector Drum, and 1 x A4 Selector Drum.
Where can I buy the FRT-MR3 online?
You can purchase the FRT-MR3 at Polymer80Outlet.
What is the hardness rating of the FRT-MR3?
The FRT-MR3 has a hardness rating of 58-60 HRC.
Is the FRT-MR3 nitride coated?
Yes, the FRT-MR3 features a nitride coating for enhanced corrosion resistance.
What is the country of origin for the FRT-MR3?
The FRT-MR3 is manufactured in the USA.
✅ Same-day shipping from Duluth, MN
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
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