[Ronin]

As far as I know there is no command for "main weapon". I mean You couldnt give a command to primary weapon whatever weapon class are chosen earliaer. You can bind a key to change weapon to SMG, and another key to Rifle etc.

If you always play with SMG, you can type these lines in console, or you can create a custom.cfg file for them in the game's main folder:

bind MWHEELUP "useweaponclass smg"
bind MWHEELDOWN "useweaponclass pistol"

You can give the following weapon classes:
"useweaponclass pistol"
"useweaponclass rifle"
"useweaponclass smg"
"useweaponclass mg"
"useweaponclass grenade"
"useweaponclass heavy"

-pistol
-rifle or sniper rifle
-Sub Machine Gun
-Machine Gun
-Grenade
-Rocket L. or shotgun

But if I'm wrong with my "main weapon" statement, and your friend realy solved it, pls let me know how he made it in his config! Then pls email it to me, or paste that part of his config file here. I was unable to solve that.