It is best to suit the bowgun that utilizes the kind of bullet that would deliver the most damage to your specific opponent.
However, bowguns are limited by the type of bullets they can equip.
The light bowgun has the advantage of being easy to handle without restricting the movement of the user during combat. Yian Kut-Ku is easily beaten by rapid fire, but be careful: while in the middle of a rapid fire burst you cannot move. Kirin are also killed more efficiently using a spray of pellet shots since they rarely stand still long enough for blademasters to deal consistent damage. Diablos are killed much more efficiently using a bowgun's Ice shots (however pellet shots work better). There are several monsters that are more easily killed by using the bowgun. Light bowguns are usually easy to make and master. Most hunters prefer light bowguns because of the fast movement and reloading speed. Due to its compact size, it does not come with as much firepower as its larger counterpart.
You can unsheathe/sheathe it much faster than a heavy bowgun due to the clear weight difference. The Light Bowgun (ライトボウガン Raitobōgan) is a bowgun that allows you to move around at a normal running speed. Left is a Silencer Part, and the right is the Long Barrel Part Light Bowguns can have additional parts that can be added or removed for improved effects.