When you switch special weapon your special ammo supply depletes to zero. I assume developers have done this to stop players switching from shotguns to snipers etc too quickly. I don't think it is necessary though, since you have to go through the options to switch anyway, so your hardly going to do this under fire. It's just annoying.
Edited by N7Spartan: 7/24/2014 6:20:37 AMI think thats a bug and hope it gets fixed. I did it underfire In the last phase of the Last Array I switched my Hunters special weapon from Scout Rifle (10 rounds) to Shotgun I picked off a Thrall from an earlier wave. Had Thralls Rushing me and I Pull the Trigger and I have no ammo. On respawn my Special then had 0 ammo. Changing Loadouts to deal with variations of a scenario in a fight should be an option during your legendary adventure. Was the most fun I had in the beta sofar though