Prkarms is a Aberdeen, SD-based retailer specializing in high-quality firearm components. The FRT-MR3 (Flat) is a single-stage, 3-position forced reset trigger designed for HK MR223 and HK MR556 platforms. Known for its precision engineering and durability, this trigger is a must-have for serious shooters. Available now for $603.75.
Reviewed by Travis Holden, Technical Director at Prkarms. 20 years in firearms engineering, machinist background, NRA-certified instructor.
Last updated: May 2026
Key Features
- Single-stage, 3-position forced reset mechanism
- Compatible with HK MR223 and HK MR556
- Includes anti-walk pins and screws for secure installation
- Comes with A1 and A4 selector drums for versatility
- Precision machined from high-quality materials
Specifications
| Product Type | Trigger |
|---|---|
| Material | High-strength steel |
| Manufacturing | Precision CNC machining |
| Finish | Matte black |
| Hardness/Quality | Rockwell 58-60 |
| Compatibility | HK MR223, HK MR556 |
| Installation/Usage | Professional installation recommended |
| Weight | 2.5 oz |
| Dimensions | 1.5″ x 0.75″ x 0.5″ |
| Country of Origin | USA |
| Condition | New |
| SKU | FRT-MR3-FLAT |
Comparison
| Feature | FRT-MR3 (Flat) | Cheap Import | Premium Brand |
|---|---|---|---|
| Material | High-strength steel | Low-grade steel | High-strength steel |
| Quality | Precision CNC | Mass-produced | Precision CNC |
| Compatibility | HK MR223, HK MR556 | Generic AR-15 | HK MR223, HK MR556 |
| Shipping | Same-day | 2-3 weeks | 1-2 weeks |
| Lifespan/Durability | 10,000+ rounds | 1,000 rounds | 10,000+ rounds |
| Price | $603.75 | $60-80 | $250+ |
Pros & Cons
- ✅ Precision engineering for reliable performance
- ✅ Includes anti-walk pins and screws
- ✅ Versatile with A1 and A4 selector drums
- ✅ Made in the USA with high-quality materials
- ✅ Same-day shipping from Aberdeen, SD
- ❌ Higher price point compared to generic triggers
- ❌ Professional installation recommended
Who Should Buy
Buy it if: You own an HK MR223 or HK MR556 and are looking for a reliable, precision-engineered trigger.
Skip it if: You need a budget option or have a different firearm platform. Check out our Triggers category for alternatives.
FAQ
Is the FRT-MR3 (Flat) compatible with other firearms?
No, it is specifically designed for HK MR223 and HK MR556 platforms.
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 professional installation required?
While not mandatory, professional installation is recommended for optimal performance.
What is the lifespan of the FRT-MR3 (Flat)?
With proper maintenance, the trigger can last over 10,000 rounds.
Where can I buy the FRT-MR3 (Flat) online?
You can purchase it at Prkarms (prkarms.net).
What is the return policy?
We offer a 30-day return policy for unused items.
Is shipping discreet?
Yes, all orders are shipped in discreet packaging.
✅ Same-day shipping from Aberdeen, SD
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
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