Rare Breed FRT-RD3 (SEF)

The Rare Breed FRT-RD3 is the MP5-family version of the trigger that created the forced reset category. It is a complete, drop-in two-stage forced reset unit with a 3-position selector (Safe, Semi, FRT). The bolt carrier's rearward travel forces the trigger back into reset after each shot and holds it until the action returns to battery, so every round still requires its own press. Rare Breed builds it from 7075 anodized aluminum and heat-treated 4140 steel; the assembled unit weighs 10.5 oz and ships with the selector, a 1/16 inch Allen key, and a 3/32 inch Allen key.

The SEF version is the one to buy if your grip frame carries traditional S/E/F letter markings rather than the modern Navy-style pictogram (bullet icons). Rare Breed is explicit that the AMBI version only functions in pictogram AMBI frames, so frame markings, not just the model, decide which RD3 you need. It fits the HK MP5, MP5K, SP5, and SP5K.

Pricing is $615 direct from Rare Breed, and purchases are capped at one per customer every 24 hours, which is the supply reality on this part. Rare Breed will not ship the RD3 to California, Connecticut, Delaware, Hawaii, Illinois, Massachusetts, Maryland, New Jersey, New York, Oregon, Rhode Island, Washington, or Washington D.C., which doubles as a useful shorthand for where forced reset triggers are restricted. Confirm current law before ordering; federal status rests on the May 2025 DOJ settlement and state rules can change.