The most common weapon in the galaxy is the blaster. Favored by militaries, gangsters, rogues, and royals alike, blasters provide dependable firepower for just about any application. The concept of firing projectiles has been around since ancient times, and in some societies guns that fire physical projectiles are still in use. Thousands of years before the Galactic Civil War, these projectile weapons gave way to energy blasters that are easier to reload and more effective than the ancient weapons. No matter their specialized purpose, the basic function is largely the same. Using an energy source, often a cartridge filled with energized gas, a blaster propels a glowing particle beam at high speed.
~ [Book] The Star Wars Book