Question concerning the Blade Runner Blaster M2019

I maybe behind on this but I just wanted to know something if anyone can give me a answer. I've wondered about the weapon that Deckard uses. What is the deal with the two triggers?

Deckards blaster is a hybrid of two guns. One is a Bulldog revolver and the other a steyr sniper rifle which lends it's two triggers and bolt mechanism.
In the film the blaster supposedly fires explosive rounds and when Decks pokes it through the hole to shoot Batty you can just hear 2 shots being fired in very rapid succession... a good reason to have 2 triggers?

Supposedly Ridley or one of the prop masters saw a disassembeld Steyr sniper rifle and thought it looked cool. Since the rifle itself could not be converted to fire they had a gunsmith insert the Charter Arms Bulldog revolver to allow it to shoot blanks. They kept the two trigger Idea. In the Rifle the front trigger is a set trigger to allow a sniper to have a hair trigger in back to keep from moving the gun to fire and miss his target. I am pretty sure no concrete idea was come up with for Deckard's gun other than for it to look good and work as a prop. For more info check out RACProps.com