Range is one of the attributes in the Respawnables, and it defines how far a gun can shoot while still being able to deal damage. This is shown by the "Range" attribute of a weapon. The more bars present, the longer the range. However, it does not represent the most effective distance is for a weapon.
All Sniper Rifles have a range of 4 bars while some Shotguns have 1, and most launcher type weapons have 2-4 bars. Generally, Assault, Launchers, Rifles Bows, and Heavy Weapons have 3-4 bars of range, and Handguns and Shotguns have around 1-2.
Explosive weapons though (apart from grenade-launching weapons) do not follow this rule, as they usually have unlimited range and are able to hit anywhere on the map.