Code:
set disable_ammo_balloony "1"
set disable_ammo_betty "1"
set disable_ammo_boaster "1"
set disable_ammo_bubbleg "1"
set disable_ammo_imperius "1"
set disable_ammo_nipper "1"
set disable_ammo_pumper "1"
set disable_ammo_splasher "1"
set disable_weapon_balloony "1"
set disable_weapon_betty "1"
set disable_weapon_boaster "1"
set disable_weapon_bubbleg "1"
set disable_weapon_imperius "1"
set disable_weapon_nipper "1"
set disable_weapon_pumper "1"
set disable_weapon_splasher "1"
Edit this and put it into e.g. a file
no-weapons.cfg. On the server console,
exec no-weapons and load a new map.
This will prevent all weapons and their ammo from spawning in the map, however players will still have the default weapons Punchy and Nipper when spawning.
You'd need a mod to remove those default weapons as well. At the time, no such mod exists.