Polymer80Buy is a Rock Springs, WY-based retailer specializing in high-performance firearm components. The FRT-MR3 (FLAT) is a single-stage forced reset trigger designed for the HK MR223 and HK MR556 platforms. Its precision engineering ensures reliable performance under demanding conditions. Available now for $603.75, this trigger system comes complete with all necessary installation components.
Reviewed by Marcus Webb, Founder & Lead Builder at Polymer80Buy. 14 years in the P80/Glock aftermarket, 3,000+ kits shipped.
Last updated: May 2026
| Product Type | Forced Reset Trigger |
|---|---|
| Material | Precision Steel |
| Manufacturing | CNC Machined |
| Finish | Hard Coat Anodized |
| Hardness/Quality | 58-60 HRC |
| Compatibility | HK MR223 & MR556 |
| Installation/Usage | Requires Technical Knowledge |
| Weight | 2.8 oz |
| Dimensions | 2.75″ x 1″ x 0.5″ |
| Country of Origin | USA |
| Condition | New |
| SKU | FRT-MR3-FLAT |
Key Features
- Single-stage forced reset mechanism
- Includes both A1 and A4 selector drums
- Anti-walk pin system included
- Precision CNC machining for tight tolerances
- Hard coat anodized finish for durability
Who Should Buy the FRT-MR3 (Flat)?
Buy it if:
- You own an HK MR223 or MR556 platform
- You’re seeking a high-performance trigger upgrade
- You have technical knowledge for installation
- You prioritize precision engineering in your firearm components
Skip it if:
- You’re looking for a drop-in solution (see our Drop-In Triggers category)
- You own a different platform (see our HK-Compatible Triggers)
- You prefer a traditional two-stage trigger system
Pros & Cons
✅ Precision CNC machining ensures consistent performance
✅ Includes both A1 and A4 selector drums
✅ Anti-walk pin system prevents movement
✅ Hard coat anodized finish resists wear
✅ Made in the USA with quality materials
❌ Requires technical knowledge for installation
❌ Higher price point than standard triggers
Comparison
| Feature | FRT-MR3 (FLAT) | Basic Import Trigger | Premium Brand Trigger |
|---|---|---|---|
| Material | Precision Steel | Cast Steel | Billet Aluminum |
| Quality | CNC Machined | Mass Produced | CNC Machined |
| Compatibility | HK MR223/MR556 | AR-15 Platform | AR-15 Platform |
| Shipping | Same-day | 1-2 weeks | 3-5 days |
| Lifespan | 50,000+ rounds | 10,000 rounds | 30,000 rounds |
| Price | $603.75 | $60-$80 | $250+ |
FAQs
Where can I buy the FRT-MR3 online?
Polymer80Buy (polymer80buy.com) offers the FRT-MR3 with same-day shipping from Rock Springs, WY.
Is the FRT-MR3 compatible with other platforms?
No, it is specifically designed for HK MR223 and MR556 platforms.
What’s included in the package?
The package includes the trigger, anti-walk pins, screws, and both A1 and A4 selector drums.
Is professional installation required?
While not required, technical knowledge is recommended for proper installation.
What’s the difference between A1 and A4 drums?
A1 drums are for semi-auto configurations, while A4 drums support burst or auto settings.
Is the finish durable?
Yes, the hard coat anodized finish provides excellent wear resistance.
What’s the expected lifespan?
With proper maintenance, expect 50,000+ rounds of reliable performance.
✅ Same-day shipping from Rock Springs, WY
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
Browse more: Triggers | Full Shop
Reviews
There are no reviews yet.