From Valve Developer Community
$scaleonly affects SMDs that come after it in the QC. Specify it before any file references!
$scaleprevents flex animation from working when using the VTA format. This limitation can be bypassed by using the DMX format.
$modelname "weapons/shell.mdl" $cdmaterials "models/weapons/" $scale 3 // before any SMDs$body shell "shell_ref.smd" $sequence idle "shell_idle.smd"