Some fan-made patches rewrite the game’s executable:
Use the built-in console with allammo bound to a macro or the IGI.ini shortcut method. It’s fast, safe, and doesn’t require third-party software. igi 1 unlimited ammo
Therefore, if you are playing the standard, unmodified version of the game downloaded from Steam or GOG, you cannot simply "toggle" a switch for infinite bullets. However, this doesn't mean you are out of luck. Players have developed workarounds over the years. Some fan-made patches rewrite the game’s executable: Use