Adamantite Weightstone bug or should it be ?

The hunters are using it all now.
Is this supposed to work on ranged attacks and critical chances ? I don't think so and maybe it's a bug.

https://imgur.com/lp0I0nh - Adamantite Weightstone
https://imgur.com/3JVwlfS - without Adamantite Weightstone
https://imgur.com/7qjPWaN - used on weapons

Definetly should not increse ranged dmg. About the crit rating im not sure. Btw there is a sticky thread for hunter bugs questions, nextime you rather should use that.

https://i.imgur.com/SCL7JTg.png
source: http://www.wowhead.com/item=28421/ad...stone#comments