12 Gauge Shotgun shells, high brass marked :”4B SPECIAL XM 257″. Combat experience in Vietnam suggested two improvements. Heavy bullet preferences dating back to the Philippine-American War were re-evaluated considering combat experience with the 5.56×45mm NATO cartridge, and advantages of a larger number of smaller No. 4 buckshot pellets were evident for some situations. These loadings were designated: Shell, Shotgun, Plastic Case, No. 4 Buck, Special, XM257. Initial production was in the same red plastic cases, but the visibility advantage for sporting use was a liability in jungle warfare; so later production used cases of a subdued green color. 1 round THIS CAN ONLY BE SHIPPED VIA FEDEX.