even though I've been playing multiplayer for a while now I still have no idea how the weapon unlocks work and what modes they apply to. If I unlock a weapon can I start using is in say for example spears and if so how do I do this

even though I've been playing multiplayer for a while now I still have no idea how the weapon unlocks work and what modes they apply to. If I unlock a weapon can I start using is in say for example spears and if so how do I do this

Weapons unlock by getting kills with them and leveling them up, every weapon level has a certain attachment associated with it. You can also change your attachments in game by pressing the back button on xbox if you play on xbox.

The weapons you can use are not limited to the map, but the killstreaks are map specific.