【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).