[FT] Weapon Mechanisms

How do members of the list envision what the various weapon mechanisms
represent?
For example I always think of the standard beam as almost a machine gun
type effect, it blankets the area of the target with shots, the closer
in the higher the percentage of possible hits.
If you design a weapon, do you envision the effect you want to simulate,
and design the mechanism to represent it, or do you think of a neat mech
and nominate what weapon this simulates