Global variable across levels

Is there any way I can have something of the sort of a global variable that exists across levels? For example, let’s say I want to use a variable to store a player’s ammo count (for various weapon types) and I want that value to persist when the player goes into another level. I know that one way this can be done is through save games, but is there any other way? Particularly, is there a way to have this stored in-memory as opposed to in a file (as in, a save game)?

Variables Stored at Gameinstance are permanent.