Proprietary rimfire cartridge developed by Remington specifically for their Model 16 semi-automatic rifle. Dimensionally distinct from .22 LR to ensure the Model 16 could not be accidentally loaded with standard .22 ammunition.
Type: Rifle
Introduced: 1914, United States
Parent case: None
Standardization: None
Bullet diameter: 0.223" (5.66 mm)
Case length: 0.68" (17.27 mm)
Max pressure: 25,000 PSI
Rim type: Rimfire
Primer: Rimfire
Typical twist rate: 1:16
Muzzle velocity: 950–1000 fps
Muzzle energy: 90–100 ft-lbs
Effective range: 75 yd
Common bullet weights: 45 gr
Primary use: Small Game, Target
Production status: Discontinued
Also known as: .22 Rem Auto
History: Introduced in 1914 for the Remington Model 16 semi-automatic rifle. The deliberate dimensional difference from .22 LR was a safety feature. The Model 16 sold modestly but the proprietary cartridge limited its appeal, and both were discontinued before WWII.
Notable firearms: Remington Model 16
Similar cartridges: .22 Long Rifle, .22 Winchester Automatic