Re: 6x45 cz527
Raising an old post, but others will want an answer if they search.
I'm in Australia, and TSE in Brisbane did the job. Extremely handy and accurate cartridge which hits much harder than .223 in real terms.
The only problem is the magazine really is .223 specific, with ribs in the mag walls which can sometimes be a bit tight on 6mm projectiles and cause feeding problems.
I have used graphite powder in the mag to reduce friction and smooth things up, and no problems since. I have read of people having those internal ribs milled out to achieve the same result.