[DarthNinja]

You set sm_iammo_enable "1" (allow infinite ammo with the command)
Then use the admin_kick command " sm_iammo <user id | name | @<team> | @all> <0 | 1>" to give just that user infinite ammo.

So,
sm_cvar sm_iammo_enable 1
sm_iammo DarthNinja 1

Would give me but nobody else infinite ammo.