Ultimately even a pistol may be used to pick up the latest weapon from a tyrant's soldier who has no more need of it.
Rocks will also work. Example: beautiful young lady, attired to attract attention, walks up to a soldier whose attention is, shall we say, attracted. While this is going on, 1 or more not-so-attractive men sneak up behind the soldier and cave in his skull. Since the soldier has no further use for the weapon(s), ammo and uniform he had (and, of course, to avoid leaving environmentally unfriendly materials laying about), these are taken. Repeat as necessary.