Firearms for firing shotshell type ammunition

In combination, a semi-automatic or automatic shotgun loaded with a rimless shotshell ammunition, comprising:

• a barrel having an interior surface defining a bore;
• a firing chamber in which the rimless shotshell ammunition is chambered, the rimless shotshell ammunition having a rimless hull;
• a seat surface at one end of a headspace and within the firing chamber, the seat surface abutting against a complimentary seat surface of the rimless hull of the rimless shotshell ammunition, wherein the seat surface is configured to prevent longitudinal forward movement of the rimless hull within the shotgun when the rimless shotshell ammunition is fired from the shotgun;
• a generally cylindrical inner surface extending through the headspace within the firing chamber, the generally cylindrical inner surface having a length of at least about 2.54 centimeters (about one inch);
• and
• a magazine sized and configured to store a plurality of shotshell ammunitions having rimless hulls within the magazine and sequentially feed shotshell ammunitions having rimless hulls into the firing chamber of the shotgun, the shotgun and the magazine being configured for detachment of the magazine from the shotgun and reattachment of the magazine to the shotgun during use of the shotgun;
• wherein the rimless shotshell ammunition comprises:
• a polymeric hull having a rimless first end comprising a primer;
• a second end of the hull defining the complementary seat surface of the hull;
• a sabot disposed within the hull;
• and
• at least one projectile disposed within the sabot.

In combination, A shotgun, a shotgun loaded with a rimless shotshell ammunition comprising:

• a barrel having an interior surface defining a bore without a forcing cone;
• a firing chamber in which the rimless shotshell ammunition is chambered;
• a generally cylindrical inner surface extending through a headspace within the firing chamber and terminating at a seat surface, wherein the seat surface abuts against a complimentary seat surface of a hull of the rimless shotshell ammunition, wherein the generally cylindrical inner surface has a diameter between about 1.775 centimeters (about 0.699 inches) and about 2.370 centimeters (about 0.933 inches), and wherein the seat surface is substantially perpendicular to the generally cylindrical inner surface;
• and
• a barrel having an interior surface, wherein the interior surface has an at least substantially uniform diameter extending from the seat surface within the firing chamber to a location proximate a distal end of the barrel;
• wherein the rimless shotshell ammunition comprises:
• a polymeric hull having a rimless first end comprising a primer;
• a second end of the hull defining the complementary seat surface of the hull;
• a sabot disposed within the hull;
• and
• at least one projectile disposed within the sabot.

In combination, a shotgun loaded with a rimless shotshell ammunition, comprising:

• a barrel having an interior surface defining a bore without a forcing cone;
• a firing chamber in which the rimless shotshell ammunition is chambered;
• a generally cylindrical inner surface of the shotgun extending through a headspace within the firing chamber, the generally cylindrical inner surface having a length of at least about 1.270 centimeters (about ½ of an inch) and a maximum diameter in a range extending from about 1.775 centimeters (about 0.699 inches) to about 2.370 centimeters (about 0.933 inches);
• and
• a seat surface within the firing chamber, the seat surface abutting against a complementary seat surface of a hull of the rimless shotshell ammunition and preventing longitudinal forward movement of the hull within the shotgun, the interior surface of the barrel defining the bore having an at least substantially uniform diameter extending from the seat surface within the firing chamber to a location proximate a distal end of the barrel;
• wherein the rimless shotshell ammunition comprises:
• a polymeric hull having a rimless first end comprising a primer for firing the ammunition, an opposing second end from which a projectile may be ejected out from the hull upon firing the ammunition, a cylindrical portion extending from the rimless first end to an open end of the cylindrical portion at the second end of the hull, an end surface of the cylindrical portion at the second end of the hull defining the seat surface of the hull, the seat surface of the hull located a distance from an outer end surface of the hull at the rimless first end, and an outer cylindrical side surface of the cylindrical portion extending from the rimless first end of the hull to the seat surface of the hull, the distance the seat surface is located from the outer end surface of the hull at the rimless first end is at least about 1.270 centimeters (about ½ of an inch), and the hull has a maximum diameter in a range extending from about 1.775 centimeters (about 0.699 inches) to about 2.370 centimeters (about 0.933 inches);
• a sabot disposed within the hull;
• and
• at least one projectile disposed within the sabot.