Energized Munitions Clip Dumps and such

"For weapons with a magazine-emptying alt fire burst like the Nagantaka Nagantaka, the burst fire will fire as many shots as there were in the magazine at the time the burst was started, but will still consume 1 ammo after every 4 shots. So after the burst there will be ammo remaining, and the burst can be used again" (c) Warframe WIKI