First create 2 binds like this:
Bindings=(Name="SniperShockA",Command="switchweapon 9 | setbind KEY SniperShockB")
Bindings=(Name="SniperShockB",Command="switchweapon 4 | setbind KEY SniperShockA")
The above will alternate between Sniper and Shock Rifle
Bindings=(Name="KEY",Command="SniperShockA")
Tada!
