Although the Spanish defenders had no machine guns, they were well equipped with modern smokeless powder rifles and a battery of two modern breech-loading 80mm mountain howitzers (Cañón de 8 cm Plasencia Modelo 1874, designed by Colonel Plasencia of the Spanish Army) that also utilized smokeless ammunition.
Some of the American forces were hindered by their equipment; in the case of the 2nd Massachusetts, the men were equipped with antiquated black-powder single-shot .45-70