The smallest production shotshell. Called a 'bore' not a 'gauge' because its small diameter doesn't fit neatly into the traditional gauge system.
Type: Shotgun
Introduced: 1874, United Kingdom
Parent case: None
Standardization: SAAMI
Bullet diameter: 0.41" (10.41 mm)
Case length: 2.5" (63.5 mm)
Overall length: 2.875" (73.03 mm)
Max pressure: 13,500 PSI
Rim type: Rimmed
Primer: 209 Shotshell
Typical twist rate: N/A (smoothbore)
Muzzle velocity: 1100–1300 fps
Muzzle energy: 140–350 ft-lbs
Effective range: 25 yd
Primary use: Small Game, Pest Control, Youth
Production status: Active
Also known as: .410 gauge · 36 gauge
History: The smallest practical shotshell, used for small game, pest control, and introducing youth to shotguns. Also chambered in revolvers (Taurus Judge, S&W Governor). Limited but dedicated market.
Notable firearms: Winchester Model 42, Mossberg 500, Taurus Judge, S&W Governor
Similar cartridges: 28 Gauge, 20 Gauge