Gun, rocket, railgun and artillery turrets - and artillery wagons - keep themselves stocked with the best ammo in reach. No interfaces, no extra buildings, no inserter spaghetti.

• On planets, construction robots bring ammo from your logistic network.
• On space platforms, the hub throws it across from its inventory.
• Upgrades itself: when your network has a full load of better ammo, the old ammo goes back to storage and the better ammo goes in. Yellow < red < uranium, rocket < explosive rocket, then higher quality.
• Pick the ammo yourself: open a turret and use the Auto-load ammo panel beside its window. The picker only shows ammo that turret can fire (with quality). Auto (best) goes back to automatic. Copy / paste settings copies the choice, and blueprints remember it.

Works with other mods

• Any modded ammo turret or artillery is handled automatically.
• Every ammo item from every mod is scored by its damage while the game loads (following projectiles, artillery shells, clusters and nested effects; area damage counts for more).
• Never uses dangerous ammo: anything that makes a nuclear explosion, spawns units (like the capture robot rocket) or has a blast wider than 10 tiles - from any mod. Ammo you load by hand is left alone.

Settings (Settings > Mod settings > Map)

Good to know

• Turrets are checked in rotation, at most once a second each, so big bases stay cheap.
• Artillery wagons are only loaded while their train is standing still.
• A turret down to its last few rounds of an ammo that has run out finishes them before switching, so it never swaps back and forth.

For mod authors

remote.call("smart-turret-ammo", "set_ammo_score", "my-ammo", 30)    -- use it, as if it did 30 damage
remote.call("smart-turret-ammo", "set_ammo_score", "my-ammo", false) -- never use it
remote.call("smart-turret-ammo", "set_turret_ammo", turret, "piercing-rounds-magazine", "normal") -- lock one turret

Source code and tests: GitHub (MIT).