Yeah, Furrymessiah is right about that one. But if the captain doesn't respond, just make the best judgement you can.
Personally, I find it's a good idea to learn about the various damage types each gun has, study which guns the Captain has on his ship, and coordinate accordingly. Guns that have large amounts of ammunition or fire quickly (Gatling, Hwacha, Banshee) will always benefit from reduced recoil IE Heavy Clip.
It's important to analyze your opponent's ships as well. Are they harassing/debilitating builds? Are they bringing lots of flamethrowers? Are they going for the DPS? More often than not, the captain will know which ammo types to bring for which ships, but again, once you get a working knowledge of things, you can play around a bit with your loadout.
Also, don't forget: If you step out of a gun before it finishes its reload, it will return to the default ammo. Likewise, if another player goes into that gun, it will return to default ammo. However, an AI player will NOT reset the ammo type.
Your personal default ammo loadout will be up to you, but as for me, I will always keep Charged Rounds if I'm dropping into a match sight unseen. YMMV.