12 Gauge
The one-gun answer — from clays to geese to the bedside, no other chambering does as many jobs, and heavy loads will remind your shoulder of that versatility.
Family
Shotshell
Introduced
1870
Origin
British and American gunmakers, 19th century
Military
US military combat and breaching shotguns (M870, M26, Mossberg 590 series)
History
The 12 gauge emerged as the dominant shotgun bore in the late 19th century and never let go, becoming the most versatile firearm chambering in existence. It serves hunters, trap and skeet shooters, police, and militaries in everything from featherweight bird loads to slugs. Shell lengths from 2 3/4 to 3 1/2 inches span an enormous power range.
What it's used for
Iconic platforms
Remington 870, Mossberg 500/590, Benelli Super Black Eagle, Beretta A400, and every double gun maker's catalog.
Common load types
Birdshot in lead and steel, buckshot, rifled slugs and sabot slugs, plus target, turkey, and reduced-recoil loads.
Reference only — not loading data, not ballistics advice, and KitID links to no ammunition sellers. Know your local law before you buy anything that goes bang.