What is gun powder used for besides guns?

Answer 1

First we must understand that there are two distinct chemical types of "gunpowder". The first is commonly referred to as Black Powder and is considered an explosive, and the 2nd is most commonly referred to as Smokeless Powder and while similar in reaction to black powder is considered a propellant.

Aside from it's use in firearms, black powder historically was used as an explosive in mining and construction. But in modern times its use in these industries has been supplanted by modern, more effective and more stable explosives such as dynamite, and ANFO, or ammonium nitrate fuel oil combinations. Black Powder is still used in some pyrotechnics and is commonly used in "blank' cartridge production for movies and in the entertainment industry.

Smokeless powder has very few uses outside of propelling projectiles in firearms. It is engineered to have limited explosive properties and is very specifically tailored to use in firearms.