Being that it is made in South Africa...by South Africans, they are hard to get, unless like me you are married to a saffa. lol.
I'm not sure on the export law into the USA, you may be stung by your own ITAR. Easily sent to UK..but if i do end up getting one i'll just get my pa-in-law to get one and mail it to me. That being said.....I'm not even sure if they are still in production but here is the official web page.

MST Ambidextrous Charging Handle 15-22, Tactical Quarter Master.