Lazer Gun (Bowgun Effects) is a free modification for the Monster Hunter game. 

The way that you can do this is by changing the values for the following:

The bow gun is used for shooting, and the way that you can change the effect that you see is by changing the values for the following:

The way that you can do this is by installing the mod and then opening the game. You will need to have the latest version of the game.

The most important thing is that this modification doesn't change any of the files that it uses.