Mechanics - Modifiers - Range
Ranged weapons have distance increments indicated in their stats.
When a target is:
Within the first increment, there is no penalty to shoot.
Between first and second increments, -2 dice to shoot.
Between second and third increments, -4 dice to shoot.
Beyond the third increment, penalties vary but at least -6. Wind, visibility, and the condition of the firearm become much more of an issue beyond the third increment. Most game combats will probably not happen at such distances anyway.
Note that ranged weapons have effective Reach values as well which change if you are within two meters of the target.