Perhaps have ammunition be automatically produced by Military factories, and in two types, Soft and Hard ammunition, the former representing small arms ammunition like rifles and the latter representing artillery shells and heavier explosives, with technology and national spirits that can upgrade either or both in the production rate.
You can also counteract this by having Civilian factories produce currency naturally, more civilian factories means more currency, which is consumed by your laws, companies, and select ministers, monthly or weekly, and if you lack enough, you lose stability and possibly war support, this should also be affected by technology and national spirits.
Both would function similar to how fuel silos produce fuel, that way the player has less to manage. And it gives reasons for the player more reasons to produce civilian factories not go totally ham on military factories.
Perhaps even have infrastructure play a role, and maybe involve energy as a mechanic through it, which could affect the efficiency of your factories.
You can also counteract this by having Civilian factories produce currency naturally, more civilian factories means more currency, which is consumed by your laws, companies, and select ministers, monthly or weekly, and if you lack enough, you lose stability and possibly war support, this should also be affected by technology and national spirits.
Both would function similar to how fuel silos produce fuel, that way the player has less to manage. And it gives reasons for the player more reasons to produce civilian factories not go totally ham on military factories.
Perhaps even have infrastructure play a role, and maybe involve energy as a mechanic through it, which could affect the efficiency of your factories.