Listen, you are doing the right thing, but do not just limit chain. You are making a mess. Limit all the ammo and add it to the production. Also, increase weight on Chain, and keep weight on Balls low. Make it available in every port from npc with +25% markup and let players craft/sell fro cheaper.
-Iron, Forge and Add perk called 'Reinforced Ammo Crates' to add +5% ammo carry capacity for chain.
(Frigate) Chain - 200, Balls - 2000 ratio ?
To stop people from complaining, add Ammo drops to npcs in case they run out and need to resupply. (Sink npc and steal their ammo).