 Guns, gun carriages, shot, and gunpowder were stored in great quantities within the main building of the castle, which had to be increased in height and its floors reinforced to accommodate the weight.By 1691, it was England's leading magazine, with 164 iron guns, 62 standing carriages, 100 ships' carriages, 7,125 pieces of iron shot, over 200 muskets of various types, 77 pikes, and 5,206 barrels of powder.This was considerably more than was held at the next largest magazine, the Tower of London.