 The maximum ranges on mounts with 15-degree elevation were (40 caliber gun), (45 caliber gun), and (50 caliber gun).The 40 caliber gun used 7.5 pounds of nitrocellulose powder, while the 45 and 50 caliber guns used 10.5 pounds of nitrocellulose in a larger case.The United States Navy acquired two protected cruisers in 1898 with four British-made export-model 4.7-inch 50 caliber guns each, along with a 6-inch main battery.