Polymer80Central is a Logan, UT-based retailer specializing in premium firearms components and accessories. The FRT-RD3 (AMBI) is a two-stage, three-position forced reset trigger designed specifically for HK MP5, MP5K, SP5, and SP5K platforms. Its ambidextrous design ensures versatility for both left- and right-handed shooters. Available now for $713.00, this trigger is a top-tier upgrade for HK enthusiasts.
Reviewed by Cody Ramirez, E-Commerce Director at Polymer80Central. 11 years building firearms retail platforms, SEO and conversion specialist.
Last updated: May 2026
Detailed Specifications
| Product Type | Forced Reset Trigger |
|---|---|
| Material | High-Grade Steel |
| Manufacturing | CNC Machined |
| Finish | Black Oxide |
| Hardness/Quality | 58-60 HRC |
| Compatibility | HK MP5, MP5K, SP5, SP5K |
| Installation/Usage | Drop-In Ready |
| Weight | 3.2 oz |
| Dimensions | 1.5″ x 0.75″ x 0.5″ |
| Country of Origin | USA |
| Condition | New |
| SKU | FRT-RD3-AMBI |
Key Features
- Two-stage, three-position forced reset mechanism
- Ambidextrous design for left- and right-handed shooters
- CNC-machined from high-grade steel
- Black oxide finish for durability and corrosion resistance
- Drop-in installation for HK MP5, MP5K, SP5, and SP5K
Who Should Buy This?
Buy it if:
- You own an HK MP5, MP5K, SP5, or SP5K and want a premium trigger upgrade
- You value ambidextrous functionality for versatility
- You prioritize durability and precision in firearms components
Skip it if:
- You’re looking for a budget-friendly trigger (see our Triggers category for alternatives)
- You don’t own a compatible HK platform
Pros and Cons
✅ Ambidextrous design for universal use
✅ CNC-machined from high-grade steel
✅ Black oxide finish for durability
✅ Drop-in installation for HK platforms
✅ Precise two-stage forced reset mechanism
❌ Higher price point compared to basic triggers
❌ Limited compatibility with non-HK platforms
Comparison Table
| Feature | FRT-RD3 (AMBI) | Budget Import | Premium Brand |
|---|---|---|---|
| Material | High-Grade Steel | Aluminum Alloy | Steel |
| Quality | CNC Machined | Cast | CNC Machined |
| Compatibility | HK MP5 Series | Generic | HK MP5 Series |
| Shipping | Same-Day | 1-2 Weeks | 3-5 Days |
| Lifespan | 50,000+ Rounds | 10,000 Rounds | 30,000 Rounds |
| Price | $713.00 | $60-$80 | $250+ |
Product Video
Frequently Asked Questions
Where can I buy the FRT-RD3 (AMBI) online?
You can purchase the FRT-RD3 (AMBI) at Polymer80Central (polymer80central.com).
Is the FRT-RD3 (AMBI) compatible with all HK MP5 models?
Yes, it’s compatible with HK MP5, MP5K, SP5, and SP5K platforms.
What makes the FRT-RD3 (AMBI) unique?
Its ambidextrous design and two-stage forced reset mechanism set it apart.
Is installation difficult?
No, it’s designed for drop-in installation, making it user-friendly.
What is the material used in the FRT-RD3 (AMBI)?
It’s CNC-machined from high-grade steel for durability.
Does it come with a warranty?
Yes, it includes a manufacturer warranty.
Is this trigger legal in all states?
Please check your local laws and regulations before purchasing.
Why Buy From Us?
✅ Same-day shipping from Logan, UT
✅ Discreet packaging
✅ 30-day returns
✅ Secure checkout
Explore More
Browse more: Triggers | Full Shop
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