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

If you own a roller-delayed HK platform and have been watching the forced reset trigger market, you already know that compatibility can be a real headache. Until now, MP5 and SP5 owners had limited options that often required permanent modification or aftermarket housings. The FRT-RD3™ (SEF) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K changes that completely. This is a drop-in design from Rare Breed that uses the standard SEF trigger housing, giving you three selectable positions: safe, semi-automatic, and forced reset. The forced reset position uses the bolt’s return energy to mechanically reset the trigger shoe forward, allowing for rapid follow-up shots that are controlled and repeatable. It is not a full-auto device, nor does it convert your firearm to machine gun status. It simply changes the mechanical relationship between the hammer and sear to create a faster, more consistent reset cycle.

Overview

The FRT-RD3™ (SEF) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K is built specifically for the HK roller-locked family. Rare Breed designed this unit to work with factory SEF (Selbstladegewehr, Einzelfeuer, Feuerstoß) trigger housings, which are the standard three-position housings found on most MP5 clones and genuine HK models. This means you do not need to swap your entire lower or modify the receiver shelf. The trigger pack drops into your existing housing, and the selector switch rotates through the familiar safe, semi, and forced-reset positions. The two-stage take-up is crisp, with a distinct wall before the break, and the forced-reset function engages only when the selector is in the third position. In safe and semi positions, the trigger behaves like a standard, high-quality aftermarket unit.

Features & Specs

• Three-position selector: Safe, Semi-Automatic, and Forced Reset (FR). The forced reset position uses bolt carrier momentum to push the trigger shoe forward after each shot, enabling rapid, controlled follow-up rounds without altering the firearm’s semi-automatic classification.
• Two-stage trigger design with a clean, predictable break. The first stage provides take-up with light resistance, and the second stage breaks cleanly at approximately 4.5 to 5.5 pounds. The reset is tactile and audible in both semi and forced-reset modes.
• Drop-in installation for HK MP5, MP5K, SP5, and SP5K models using standard SEF trigger housings. No permanent modification, drilling, or filing required. Compatible with both genuine HK and licensed clones such as PTR and Zenith, provided they use a standard SEF housing.

Who It’s For

This trigger is for the experienced HK owner who wants to push the performance of their roller-locked firearm without converting it to a different platform. It is ideal for shooters who compete in PCC divisions, run drills that reward fast splits, or simply want a more engaging range experience. The FRT-RD3™ (SEF) Two-Stage (3-Position) Forced Reset Trigger for the HK MP5, MP5K, SP5 & SP5K is also a strong choice for collectors who want to retain the classic SEF housing look while gaining modern trigger technology. If you are comfortable with basic trigger pack installation and understand how forced reset mechanisms operate, you will have no trouble with this unit. It is not recommended for users who are unfamiliar with their firearm’s internal safety systems or who are unwilling to verify compatibility with their specific trigger housing.

Shipping & FFL

This item ships directly to your address. No FFL transfer is required for this trigger component because it is not a firearm frame or receiver. However, you must be at least 18 years old to purchase and comply with all applicable federal, state, and local laws regarding trigger installation. Some states and municipalities have restrictions on forced reset triggers. It is your responsibility to verify legality before ordering. Rare Breed triggers are designed to comply with current ATF guidelines, but regulations can change. If your order is canceled due to legal restrictions, a refund will be issued minus a restocking fee. Always check your local laws before purchasing any aftermarket trigger system.