20-gauge shotgun

20 gauge
Three 23⁄4" 20-gauge shells (right) loaded with #71⁄2 birdshot.
Type	Shotgun
Place of origin	United Kingdom
Production history
Manufacturer	Various
Variants	21⁄2" (63.5 mm) 23⁄4" (70 mm) 3" (76.2 mm)
Specifications
Case type	Rimmed, straight
Bullet diameter	.615 in (15.6 mm)
Shoulder diameter	.684 in (17.4 mm)
Base diameter	.697 in (17.7 mm)
Rim diameter	.766 in (19.5 mm)
Rim thickness	.0484 in (1.23 mm)
Case length	2.76 in (70 mm)
Primer type	Shotshell Primer
Maximum pressure	12,000 psi (83 MPa)[1]
Ballistic performance
Bullet mass/type Velocity Energy 273.438 gr (18 g) 5⁄8 oz. Remington Slugger 23⁄4" Slug 1,800 ft/s (550 m/s) 1,575 ft⋅lbf (2,135 J) 273.438 gr (18 g) 5⁄8 oz. Remington Slugger 23⁄4" Slug 1,580 ft/s (480 m/s) 1,513 ft⋅lbf (2,051 J) 468 gr (30 g) Federal 23⁄4" 11⁄8 oz. #3 Buckshot 1,200 ft/s (370 m/s) 1,496 ft⋅lbf (2,028 J) 546.875 gr (35 g) 11⁄4 oz. Fiocchi 3" #5 Shot 1,200 ft/s (370 m/s) 1,748 ft⋅lbf (2,370 J) 382.812 gr (25 g) 7⁄8 oz. Winchester 23⁄4" #71⁄2 Shot 1,200 ft/s (370 m/s) 1,224 ft⋅lbf (1,660 J)

The 20-gauge shotgun, also known as 20 bore, is a type of smoothbore shotgun. 20-gauge shotguns have a bore diameter of .615 in (15.6 mm), while the 12-gauge has a bore diameter of .729 in (18.5 mm).^[2] 12-gauge and 20-gauge shotguns are the most popular gauges in the United States.^[3][4] The 20-gauge is popular among upland game hunters, target shooters, and skeet shooters.^[4]