A breech flag. I wonder how many here know what one of those are. I've seen them advertised but have never run across a range which requires their use. I've even had one or two autopistols come with yellow or orange plastic flags for this use. The only instance I've seen where they might serve a purpose is with SA revolvers. Since you cannot swing out your cylinder you can only lay it down with the loading gate open. And since you cannot swing out the cylinder you could never insert a flag into the cylinder under the hammer.Our process for range safety is very clear. When 'end detail is called ALL shooting stops, shooters have to make safe and show clear ALL firearms. If you have a magazine loaded you pocket it otherwise mags are left so they can be seen at the firing point. Once done ALL shooters stand back from the firing points, at least 6 feet. The RCO (Range Conducting Officer) will then announce "Range clear, you may now go forward and change or patch targets".
Once done the RCO will then announce "Range is closed, eyes and ears, you may load and carry on..".
Once I have finished shooting I must make eye contact or call for the RCO and ask permission to "box my firearm". All such 'boxing' (returning to a case) and 'unboxing' is done only at the firing point and only with the RCO's say so.
Our range is safe, very safe.
Edit: meant to say that ALL firearms, when made safe, must show a breech flag. No exceptions.