Patent ID: 8240252

Claim:
A 22, .22-250, .223, .243, .25-06, .270, .300, .30-30, .30-40, 30.06, .303, .308, .357, .38, .40, .45, .45-70, .50 BMG, 5.45 mm, 5.56 mm, 6.5 mm, 6.8 mm, 7 mm, 7.62 mm, 8 mm, 12.7 mm, 14.5 mm, 20 mm, 25 mm, 30 mm, or 40 mm caliber ammunition article comprising: an ammunition casing, the casing defining a generally cylindrical hollow body having first and second ends and consisting of a caselet and a cap; a propellant disposed and confined within said hollow body and a primer for disposed at the first end of said casing in combustible communication with said propellant; wherein the caselet comprises a polymeric material that has a room temperature (about 23° C.) notched Izod impact strength, measured in accordance with ASTM D256-00, greater than about 10 ft lbs/in and that has a ratio of notched Izod impact strength at room temperature to notched Izod impact strength at about −40° C. of less than about 4.