Ray Guns fire clusters of charged particles. These impact the target with kinetic energy, and also cause electic shock. The net effect is similar to that of a lightning bolt.
Firing protons, these weapons have little electric charge and cause a good deal of kinetic damage. Firing lighter electrons, they have a greater charge and less kinetic impact - which is likely to stun living creatures and robots. A blaster set to stun will not kill on a failed Death Test, only cause a minute of unconsciousness per point of negative outcome. It has no effect whatsoever on construction, but can stun both living creatures and robots.
Because of their versatility, blasters are very popular with police and paramilitary forces, as well as with civilians. It is not really a hardcore military weapon.
These are blasters à la Star Wars and other pulpy science-fiction shows.