depends on ambient temperature if it is 100 degrees out side i usually have a rag soaked in ice cold water i apply to bbl between shots
if it is cool out side say 45-50 i shoot wait a minute or two shoot the wait about 5 minutes
this is for shooting groups
for sighting in i make sure bbl is completly cool your fist shot will be out of a cold bbl if the load groups well it will be fine on follow up shots