Tobar said:
Not to keep us off topic but just in the defense of the EU. It's first purpose is to explain and and expand upon the things we see in the films.
And repeat essentially the same story in both pre-film and post-film history.
As for an explanation of how blasters work:
In particle-beam based blasters, like the E-11 used by stormtroopers, a small amount of high-energy gas moved from the heter valve to the chamber commonly called the XCiter. In the XCiter chamber, the gas was energized by the power pack, then passed into the actuating blaster module, which, when assisted by the components in the barrel, processed the now extremely high-energy gas into a compressed beam of intense energy particles, coupled with intense light, which generated the deadly high-energy particle beam fired from most blasters. In these blasters, the combination of superhot laser-light and a compressed bolt of intense energy particles formed the deadly bolt.
Blaster bolts usually dissipated in a small, but violent explosion of extreme heat and force upon contact with an unshielded surface, sometimes leaving blast points.
In other words, essntially a plasma gun.