Rare Breed FRT-RD3 (AMBI)

The Rare Breed FRT-RD3 (AMBI) is the ambidextrous-selector version of Rare Breed's MP5-family forced reset trigger. Mechanically it matches the SEF model: a complete drop-in two-stage forced reset unit with a 3-position selector (Safe, Semi, FRT), built from 7075 anodized aluminum and heat-treated 4140 steel, 10.5 oz assembled, fitting the HK MP5, MP5K, SP5, and SP5K. The difference is the selector, which exposes a lever on both sides of the lower for left-handed shooters and anyone who runs the gun from either shoulder.

The fitment caveat is the one to get right. Rare Breed states the AMBI version only functions with AMBI grip frames that carry modern Navy-style pictogram markings (bullet icons) rather than the older S/E/F letters. If your frame has letter markings, you want the SEF model instead; the selector geometry is not interchangeable between the two. Confirm your grip frame's markings before ordering.

Pricing is $620 direct from Rare Breed with the same one-per-customer-per-24-hours cap as the SEF model. Rare Breed does not ship the RD3 to California, Connecticut, Delaware, Hawaii, Illinois, Massachusetts, Maryland, New Jersey, New York, Oregon, Rhode Island, Washington, or Washington D.C. Verify current federal, state, and local law before purchase; federal status rests on the May 2025 DOJ settlement and state rules can shift.