found glitch:
have chainsaw as secondary gun and have a magnum/either shotgun as primary. with ur primary weapon out click then press space VERY VERY quickly. u should have 99 ammo in shotgun/ magnum. for hunting rifle do this with chainsaw equipped then change to rifle :)
 "The Last Stand"){kind=icon}
 "Tactical Assassin Substratum"){kind=icon}
 "Z-Rox"){kind=icon}
 "Crush 2"){kind=icon}