Half cock

[Strangely Brown]

on a loaded rifle at a range when the RO says "make safe", "make safe" to me means unload the chamber & magazine & if available, insert a chamber flag, just remember members here are not all current or ex-service personnel, so army doctrine does not/should not apply

Make safe in a service rifle competition in the UK means something slightly different:
Remove the magazine, unload/remove any round from the chamber (if any) and fire the weapon on an empty chamber. Then apply the safety catch and reattach the magazine. The magazine will be assumed to be charged ready for the next phase of the competition.
All done with the rifle pointing at the back stop of the range.