Simple blow‑back, open‑bolt, selective‑fire; rate of fire 600–1,250 rpm depending on model
Trigger type
Selective fire (safe, semi, full auto — Mk II) or full auto only (some variants)
Two‑stage trigger: semi‑automatic (first pull) and fully‑automatic (second pull) on early models; later models use a single‑stage full‑auto trigger with a selector switch
Sights
Fixed front post, fixed peep rear — crude but functional
Rotary drum rear sight with 50, 100, 200, 300 yard settings; hooded front post; optional adjustable rear sight on later police variants