ATP= 12 ga, Tactial, Police/Milatary , factory 7 + 1 pump. with a 20" Barrel. This is 1970s era shotgun in absolutely beautiful condition that has never been molested. This was their introduction series of milatary, Police, Tactial shotguns. The blueing is really in great shape with no ware marks. The wood has beautiful grain and is also in perfect condition. It's rare finding any weapon 40 to 50 years old in this great of shape. Love the mag tube being the same length as the barrel.