Life is somewhat different in South Africa. There, you carry your firearm with you right up to the security checkpoint. You then head off to the 'Special Baggage Services' desk where you unload your firearms in the slots provided (an unloaded firearm being worse than useless in South Africa) and you then present it, and the applicable licence to a police officer who notes down the weapon type, serial number, number of rounds of ammunition etc; sticks it in a bag and seals it. S/he then relieves you of R50 (probably gone up by now - the last time I did this was in 1999) and the bag (with ammo clip included) is then taken by ground staff and given to the Captain. At the other end, thye ground staff take it from the flight deck and you collect it from baggage services.
I did this once with an American friend in tow going from CPT to JNB - I was carrying my SIG P226 and my HK MP5K on me and had my Sites Spectre in a special case. This collection raised an eyebrow or two with the SAPS officers (who turned bright green with envy)
and I suspect caused my friend to cut short his trip somewhat.