In this video I set up a little test bench/shooting range and we let it rip with a bunch of different ammo and weapon types! Check it out, it should help you decide which ammo and weapon is best for which situation.
We go through the Light Autocannon, Heavy Autocannon, Rotary Autocannon aka the minigun, Battle Cannon, Artillery, and the Bertha.
Stormworks Search and Destroy ammo weapon test