The weapon uses ion cartridges found in the outer mining planets in the ionic galaxies. Wookies first discovered the ions as a propellent to keep bugs off of their fur. Until the wookies learned the ion compound combusted when under high pressure. 50 wookies died from this sad but neccessary understanding of the ions now used in blaster rifles.
When word of this tragic incident reached the republic they quickily mass produced this for use in guns that would fire a concentrated beam of energy that would realign organic material effectively splitting apart the internal make up of the atoms. Or, in a shorter sense killing the person and hurting them very bad while doing so.