Armory, Arsenal and Magazine have related but usually distinguishable technical military senses.
Armory once carried the meanings now associated with arsenal and magazine, but in current use it has commonly two applications: one, a public building in which troops (as of the National Guard) have their headquarters and facilities (as for drill and storage); the other, an establishment under government control for the manufacture of arms (as rifles, pistols, bayonets, and swords).
Arsenal in its narrow sense is applied to a government establishment for the manufacture, storage, and issue of arms, ammunition, and related equipment: in popular and especially in figurative use the word usually suggests a store of or a storehouse for weapons and ammunition.
- weapons from the arsenal of poetic satire
—Reedy - make America the arsenal of the democracies
Magazine is strictly applied to a storehouse for all sorts of military and naval supplies including especially arms and ammunition. In extended use it often more narrowly suggests a storehouse for explosives.
- a powder magazine
- as when high Jove his sharp artillery forms, and opes his cloudy magazine of storms
—Pope - an educated man stands, as it were, in the midst of a boundless arsenal and magazine, filled with all the weapons and engines which man’s skill has been able to devise from the earliest time
—Carlyle
In extended use magazine is applied to a supply chamber (as in a gun for cartridges, in a camera for films, or in a typesetting machine for matrices).