CZ's supply chain is spotty at best. The magazines will be available again. My recommendation is to check
CZ parts
at least weekly, better bi-weekly. They are in Czechoslovakia, but ship to USA quickly when parts are in stock. Watch out for scammers.
I really like my CZ 457, excellent gun. Didn't like the plastic cocking indicator though, tends to get bent and mine was boogered up from the factory, so made my own:
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