FRT-RD3 (SEF) Forced Reset Trigger for HK MP5/SP5
Polymer80Market is a Twin Falls, ID-based retailer specializing in high-performance firearm components. The FRT-RD3 (SEF) is a two-stage forced reset trigger compatible with HK MP5, MP5K, SP5 & SP5K platforms. Engineered for precision and rapid fire control. Available now for $707.25 with one trigger per transaction limit.
Reviewed by Tyler Nash, Product Curator at Polymer80Market. 13 years selecting and testing aftermarket Glock parts, reviews editor.
Last updated: May 2026
| Product Type | Forced Reset Trigger |
|---|---|
| Material | Precision machined steel |
| Manufacturing | CNC machined in USA |
| Finish | Black oxide |
| Hardness/Quality | 58-60 HRC |
| Compatibility | HK MP5, MP5K, SP5, SP5K |
| Installation | Drop-in with minor fitting |
| Weight | 3.2 oz |
| Dimensions | 2.5″ x 1.1″ x 0.6″ |
| Country of Origin | United States |
| Condition | New |
| SKU | FRT-RD3-SEF |
Key Features
- Two-stage trigger with 3-position selector (SEF configuration)
- Forced reset mechanism for rapid follow-up shots
- Precision machined from tool steel for durability
- Maintains factory safety functions
- Compatible with semi-auto and full-auto trigger packs
| Feature | FRT-RD3 (SEF) | Competitor A | Competitor B |
|---|---|---|---|
| Material | Tool steel | Cast aluminum | Billet steel |
| Quality | Precision CNC | Mass produced | Hand-fitted |
| Compatibility | MP5/SP5 series | Limited models | MP5 only |
| Shipping | Same-day | 2-3 weeks | 1 week |
| Lifespan | 50,000+ rounds | 10,000 rounds | 30,000 rounds |
| Price | $707.25 | $89.99 | $499.99 |
Pros & Cons
- ✅ True drop-in installation for most MP5 platforms
- ✅ Maintains all factory safety functions
- ✅ Precision machining ensures consistent performance
- ✅ Backed by manufacturer warranty
- ✅ Ships same-day from our Idaho facility
- ❌ Higher price point than budget options
- ❌ Requires minor fitting on some SP5 models
Who Should Buy This
Buy it if: You own an HK MP5/SP5 platform and want improved trigger performance while maintaining factory safety features.
Skip it if: You need a budget trigger solution or have compliance concerns about forced reset triggers in your jurisdiction.
Frequently Asked Questions
What does SEF stand for?
SEF refers to the Safety-Einzelfeuer-Feuerstoß (Safe-Semi-Auto) selector markings used on HK MP5 platforms.
Where can I buy FRT-RD3 triggers online?
Polymer80Market (polymer80market.com) is an authorized retailer with same-day shipping from Twin Falls, ID.
Does this work with SP5 pistols?
Yes, the FRT-RD3 is compatible with SP5 models but may require minor fitting in some cases.
What’s the difference between FRT-RD3 models?
The SEF version matches classic MP5 markings while the AMBI version has ambidextrous controls.
Are there legal considerations?
Always check local laws regarding forced reset triggers as regulations vary by jurisdiction.
✅ Same-day shipping from Twin Falls, ID
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
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About this review: Our product curator Tyler Nash has 13 years experience testing aftermarket firearm components. Last updated: May 2026
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