Underbarrel flashlights, how do they work?

[Pandema 352]

How in God's name do you attach the weapon flashlights to the gun? It's driving me crazy.

[Shadyfizzle 80]

You need a RIS handguard, since the stock one and the magpul one do not have the necessary rails. Once you find that you should just be able to drag the flashlight onto your gun!

[Kegaro 19]

^^ What he said ^^ 

 

You need the right hand guard that allows you to attach it.