Polymer80Hub is a Johnson City, TN-based retailer specializing in high-performance firearm components. The FRT-MR3 (FLAT) is a single-stage, three-position forced reset trigger designed specifically for the HK MR223 and HK MR556 platforms. Its precision engineering ensures reliability and smooth operation. Available now for $603.75, this trigger is ready to enhance your shooting experience.
Reviewed by Derrick Cole, Range Master & Reviewer at Polymer80Hub. 19 years competitive shooting, product tester for 3 manufacturers.
Last updated: May 2026
| Product Type | Forced Reset Trigger |
|---|---|
| Material | High-Grade Steel |
| Manufacturing | CNC Machined |
| Finish | Hardcoat Anodized |
| Hardness/Quality | Rockwell 50+ |
| Compatibility | HK MR223, HK MR556 |
| Installation/Usage | Drop-In Ready |
| Weight | 2.8 oz |
| Dimensions | 2.5″ x 1.2″ x 0.8″ |
| Country of Origin | USA |
| Condition | New |
| SKU | FRT-MR3-FLAT |
Key Features
- Single-Stage Operation: Provides a consistent trigger pull for improved accuracy.
- Three-Position Selector: Offers safe, semi, and full-auto modes.
- Anti-Walk Pins Included: Ensures secure installation and prevents pin movement.
- Precision CNC Machined: High-grade steel construction for durability.
- Hardcoat Anodized Finish: Resistant to wear and corrosion.
Who It’s For
Buy it if: You own an HK MR223 or HK MR556 and are looking for a reliable, high-performance forced reset trigger. This is ideal for competitive shooters, tactical operators, and firearms enthusiasts who demand precision and durability.
Skip it if: You are looking for a budget option or need a trigger for a different firearm platform. Check out our Triggers section for alternatives.
Pros & Cons
- ✅ Precision CNC machining ensures high-quality construction.
- ✅ Hardcoat anodized finish resists wear and corrosion.
- ✅ Includes anti-walk pins for secure installation.
- ✅ Compatible with HK MR223 and HK MR556.
- ✅ Drop-in ready for easy installation.
- ❌ Higher price point compared to budget options.
- ❌ Limited compatibility to specific HK models.
Comparison
| Feature | FRT-MR3 (FLAT) | Budget Import Trigger | Premium Brand Trigger |
|---|---|---|---|
| Material | High-Grade Steel | Cast Aluminum | High-Grade Steel |
| Quality | CNC Machined | Cast | CNC Machined |
| Compatibility | HK MR223, MR556 | AR-15 | AR-15 |
| Shipping | Same-Day | 1-2 Weeks | Same-Day |
| Lifespan/Durability | 50,000+ Rounds | 10,000 Rounds | 50,000+ Rounds |
| Price | $603.75 | $60-80 | $250+ |
FAQ
Where can I buy FRT-MR3 (FLAT) online?
You can purchase the FRT-MR3 (FLAT) directly from Polymer80Hub at polymer80hub.com.
Is the FRT-MR3 (FLAT) compatible with other HK models?
No, the FRT-MR3 (FLAT) is specifically designed for the HK MR223 and HK MR556.
What is 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.
Is installation difficult?
No, the FRT-MR3 (FLAT) is drop-in ready and includes anti-walk pins for secure installation.
What is the warranty on this product?
The FRT-MR3 (FLAT) comes with a 30-day return policy from Polymer80Hub.
How does the FRT-MR3 (FLAT) compare to other triggers?
The FRT-MR3 (FLAT) offers superior build quality and compatibility with HK MR223 and MR556, making it a top choice for those platforms.
Can I use this trigger in competitions?
Yes, the FRT-MR3 (FLAT) is suitable for competitive shooting due to its precision and reliability.
✅ Same-day shipping from Johnson City, TN
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
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