The STI Duty One CO2 Air Pistol (also called the ASG STI Duty One) is a licensed replica of the real STI Duty One 1911-style semi-automatic pistol, made by Action Sport Games (ASG) in Denmark. It's a fun, budget-friendly CO2-powered .177 caliber (4.5mm) steel BB pistol designed for backyard plinking, target shooting, and general airgun recreation.
Key specs and features
Power source: 12g CO2 cartridge (stored in the grip with an easy-load system).
Action: Semi-automatic only. Comes in two main versions:
Blowback — Full-metal slide reciprocates with each shot for realistic recoil, slide movement, and sound (very immersive, feels more like a real 1911).
Non-blowback (NBB) — No moving slide, which gives quieter operation, higher shot count, and slightly better consistency.
Magazine: Drop-out stick-style mag holding 16–20 steel BBs (depending on version).
Velocity: Around 350–400 fps with steel BBs (enough for fun plinking and paper targets; not for serious pest control).
Barrel: Threaded on many models (1/2" UNF or similar) so you can add a silencer/moderator.
Other goodies: Integrated Weaver/Picatinny accessory rail under the barrel (perfect for a laser or light), high-rise beavertail grip with STI logo, full-metal slide and frame on most versions, fixed or adjustable sights, manual safety, and authentic STI markings plus a unique serial number.
Size/weight: About 8.7–8.8" long, ~4.5–4.7" barrel, weighs around 1.8 lbs — feels solid and well-balanced like a real duty 1911.
Build Quality
It's built mostly from metal for a premium heft, with polymer grips that have nice checkering and STI branding.
Performance and shooting feel
Shooters love it for the realistic handling—especially the blowback version, which cocks the hammer and gives that satisfying “snap” with every trigger pull. Reviews consistently call the trigger crisp and light for a CO2 gun.
Shot count is excellent: 80–100+ rounds per 12g CO2 cartridge (higher on non-blowback models). BBs fly straight enough for casual target shooting out to 20–30 yards, and the threaded barrel + optional suppressor makes it pretty quiet for backyard use.
It’s not regulated like a PCP, so power drops as the CO2 cools down, but for plinking it’s reliable and rarely has issues like double-feeds when kept clean.Why people like it (and who it’s for)
Great value — Incredibly cheap for a high qulity CO2 Pistol.
Realism — Licensed by STI International (a real Texas-based 1911 manufacturer), so it looks and feels like a high-end duty pistol.
Fun factor — Perfect for new shooters, training drills, or just casual plinking. The blowback model is especially popular for that “movie gun” feel.
Easy to accessorize — Rail + threaded barrel let you customize it easily.