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]

Quick Facts Type, Place of origin ...

20 gauge
3 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)

Close

20 lead balls of the diameter of a 20 gauge shotgun bore weigh one pound, while just 12 lead balls of the diameter of a 12 gauge shotgun bore equals the same weight.^[2] A 20 gauge shotgun is more suitable for hunting certain types of game or for some hunters because it may have less felt recoil than an identical shotgun in a larger gauge, ^[5] and guns may be smaller and weigh less, though this has changed since the introduction of the 3 inch magnum shotshell.^[3]

Regarding the yellow body tube color that 20gauge ammunition usually has, it has been reserved in SAAMI documentation saying "SAAMI has reserved yellow for 20 gauge ammunition" "This ammunition shall have a body tube that is primarily yellow" "Yellow shall not be used for any other gauge/bore shotshell body" "No other recommendations are made as to the color of service body tubes for other gauges/bores"^[6] This color designation may be designed to aid in identifying 20 ga shells. A 20 ga shell if mixed in with 12 ga. shells will enter the chamber and lodge inside the bore at the end of the chamber. If a 12 ga shell is loaded and fired behind the lodged 20 ga shell the result is catastrophic. ^[7]

20 gauge shotguns are especially suitable for hunting game birds such as quail, grouse and mallards when using lead-free birdshot. A 20 gauge buckshot load would most commonly be utilized in close- to mid-range self defense scenarios.^{[citation needed]} While slug loads are ballistically less accurate than rounds used in rifles, powerful, high-grain slug loads can provide improved ballistics for hunting deer when paired with a rifled barrel.^[8]

While the 20 gauge is generally perceived to have less felt recoil than the 12 gauge, there are too many variables, including gun weight, type of shotgun, stock pattern, shot weight, shell size, etc. for that opinion to be a fact.^[9][10] There may be little to no difference between the two when using target ammunition. Loads for waterfowl will tend to produce more felt recoil in a 12 gauge shotgun than in a 20, but this may not be the case depending on the gun used.^[9] Full-power 20 gauge shells fired from a light 5 lb (2.3 kg) gun will have more felt recoil than those fired from a heavy 7 lb (3.2 kg) gun.^[11] To do a true comparison, two identical shotguns, one in 12 and one in 20, with identical ammunition (other than gauge) have to be compared. In those cases, the 12 gauge does generate more recoil energy than the 20.^[9][12]

• Shotgun shell
• Cartridge (firearms)