Finish your AR15 lower with this comprehensive Mil-Spec Lower Parts Kit. Includes every pin, spring, detent, and component needed for a fully functional lower—minus buffer tube assembly and stock. The phosphate-coated single-stage trigger delivers crisp, reliable 5.5–7 lb pull with proven mil-spec geometry. All parts are precision-machined for drop-in compatibility with any Mil-Spec AR15 lower receiver.

Single-stage Mil-Spec trigger
trigger spring
hammer
hammer spring
disconnector
disconnector spring
trigger pin
hammer pin
selector
selector detent
selector detent spring
bolt catch
bolt catch plunger
bolt catch spring
bolt catch roll pin
magazine catch
magazine catch button
magazine catch spring
takedown pin
pivot pin
takedown/pivot detents (2)
takedown/pivot detent springs (2)
buffer retainer
buffer retainer spring
trigger guard
trigger guard roll pin
bolt release roll pin
A2-style pistol grip
pistol grip screw
pistol grip lock washer

Every One Horse rifle and component is made in America with uncompromising standards. We use U.S.-sourced materials, U.S. manufacturing, and strict quality control at every step. No shortcuts, no imported surprises — just dependable parts built by people who take pride in American craftsmanship. When you run One Horse, you’re running gear you can trust every single day.