Ripp is 100% correct in his guess that most competitive shooters in the USA load their own rifle ammo. Small bore and some Military match shooters are the exceptions. In some Mil-Matches you have to shoot the ammo you are issued.

As far as this goes------------"Thank you, as I said earlier its " popularity" is essentially an American thing"

I'd agree! As I'd expect it to be.

The USA has the largest number of privately owned guns of any country in the world so it follows the most real rifle-men would be here too.