This forum is for technical support on Blizzard’s Diablo II (2000) and its extension Diablo II: Lord of Destruction.
There are no Assault Rifles in the Diablo II game; your question seems to relate to Activision’s Call of Duty. Support for Activision’s games on Blizzard forums is limited; you can find some information on this here.
I suggest you search for the answer to your question on the internet… perhaps you can find some other forums where Call of Duty players help others.
Good luck !