Hi Gordon,
GSC sells in the USA as well. Any bullet we make is also available and made in the USA.
The RSA gun laws, as elsewhere in the world, was concocted by people who crave control. They have no idea about firearms related matters and disregard the fact that the law abiding gun owner is actually on their side.
It has always been the case that, to buy anything that is classed as ammunition in RSA, required a firearm license for the cartridge in question. Ammunition is classed in RSA as cartridges, primed cases and primers. Bullets and unprimed cases are not classed as ammunition. If any visitor enters the country with a rifle, a temporary license for that rifle is issued by customs. That temporary license can be used by a visitor as any license issued to an RSA citizen would be used. If a gun shop gives you any trouble about that, the easiest is to ask for the owner, as s/he should know the law.