Despite having a small conveyor port on the bottom missiles cannot be fed to the small turrets in any configuration. This renders the turret useless in survival.

Possible turret configurations.

Left: Attached to small port on large convayor with ammo in the cargo container.
Center: Attached directly to medium cargo container with missles inside and no dice.
Right: Attached via small pipes.

A possible solution to this is to make these smaller missile turrets do a bit less damage to balance their compactness, and give them missiles that can pass through small pipes as vanilla missile ammo isn't allowed through small conveyors.