Sometimes i cant do a taunt after a kill , right on d-pad seems to do nothing even when pressed first , The A button does the jump when pressing both. Alo i have noticed often that snipers i hit with my rail gun have a full green-only bar that seem to take damage as it gold armored+overheal . it would take a full clip of rail hits to take out the sniper , each shot was hitting since i was seeing the health bar move but it would take out 1/6 of the health bar per hit.
The Sniper takes 5 rail gun shots to kill if he is wearing gold armor. (All classes vs rail gun shots to kill is listed in my tank guide which you can access by clicking my signature picture (not the link).)