I belong to two clubs one is outside and has many different ranges, one for rimfire, one for highpower rifles, one for pistols, and then the shotgun, ranges, blackpowder and archery...
The rules are the same on all. when the line is hot shooters can step forward to the shooting positions and load and fire. By agreement or by the range safety officer if its busy, or in a match the line is called safe.
When the range is safe, the safety flag is down guns are on the bench magazines out , slides and bolts open, and the red flashing lights are on. The line is inspected and all shooters can go down range and change targets. No one is allowed forward of the yellow safety line, no gun or ammo handling. WHen target changes are complete the line is called hot flag is raised and shooters may step forward of the yellow safety line to load handle and fire.
Shotgun ranges are hot while the birds are flying shooters are in position and rounds are being shot, trap skeet, sporting clays. The Line is called safe and all shotguns are made safe racked in a RACK and then shooters may go down to put cases of birds in the automatic throwing machines.
My indoor club is a bullseye pistol club the same rules apply but the bullseye commands are called,and the line officer inspects all firearms before the shooters go forward to score. Cold= safe. The club room is always Cold or safe no handling of loaded firearms, holstered is ok.