FRT-RD3 (Ambi) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K

Overview

The FRT-RD3 (Ambi) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K represents a significant engineering evolution in trigger system design for the roller-delayed platform. Manufactured by Rare Breed, this drop-in assembly integrates a three-position selector with a forced-reset mechanism that delivers a distinct two-stage pull. The FRT-RD3 (Ambi) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K is constructed from heat-treated steel components and precision-machined 7075-T6 aluminum housing, ensuring dimensional stability under sustained fire. Designed specifically for HK-pattern firearms, this trigger replaces factory trigger packs without permanent modification to the host receiver. The ambidextrous selector configuration accommodates left-handed and right-handed operators equally, with tactile detents for each position.

Features & Specs

The FRT-RD3 (Ambi) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K offers three distinct operating modes, each engineered to specific mechanical parameters. The trigger system uses a patented forced-reset cam that re-engages the sear automatically after each shot, returning the trigger to the reset point without requiring full manual release. The two-stage pull breaks at a consistent 4.5 to 5.5 pounds with minimal overtravel, verified through Rare Breed’s quality control testing. All internal engagement surfaces receive a controlled surface finish treatment to reduce friction and maintain repeatable lock time.

• Three-position selector: Safe, Semi-Automatic, and Forced-Reset positions with positive detent indexing
• Ambi selector lever set included for left- or right-side configuration without additional parts
• Drop-in design for HK MP5, MP5K, SP5, and SP5K variants; no permanent receiver modification required

The FRT-RD3 (Ambi) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K uses a dual-stage sear engagement geometry that provides a defined wall before break. The forced-reset cycle is mechanically limited to prevent out-of-battery ignition. Each unit is serialized and inspected to Rare Breed’s manufacturing specifications.

• Two-stage pull with forced-reset cycling; reset is tactile and audible
• Heat-treated alloy steel hammer, sear, and disconnector components
• 7075-T6 aluminum housing with Type III hard coat anodized finish

Who It’s For

This trigger is designed for HK MP5, MP5K, SP5, and SP5K owners who require a mechanically repeatable trigger system with a defined two-stage break and forced-reset functionality. The FRT-RD3 (Ambi) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K is suited for competitive shooters, firearms instructors, and collectors who want a factory-spec drop-in trigger that maintains the platform’s original manual of arms. Users should have mechanical familiarity with their host firearm’s trigger group installation process. This product is not intended for use in full-auto registered receivers or any configuration that bypasses the semi-automatic function of the trigger’s safe and semi positions.

• Designed for semi-automatic HK roller-delayed blowback carbines and pistols
• Requires user installation or qualified gunsmith fitting; includes installation guide
• Compatible with factory HK lower receivers and aftermarket housings that accept standard trigger packs

Shipping & FFL

This FRT-RD3 (Ambi) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K is classified as a firearm component and does not require transfer through a Federal Firearms License (FFL) dealer for shipment to most states. However, customers must comply with all applicable federal, state, and local laws regarding the purchase and possession of trigger assemblies. Some jurisdictions impose restrictions on forced-reset trigger systems. It is the buyer’s sole responsibility to verify legality in their jurisdiction before ordering. Rare Breed triggers are serialized; retain all documentation provided with the product. No returns are accepted on installed trigger packs. Shipping is via insured ground service to the billing address on file.