For those who have also had to replace the O-ring seal on the bolt of their CZ200 I have found a good source of them here in South Africa.
BMG which has offices in the country sells the correct O-ring for about R2 each. Buy a few. Their item code is RMT 1X3 VF
I never had to replace those rings until I installed the 10 round magazine. I get about 250 pigeons per O-ring replacement.
It helps if you put a little silicone grease on the O-ring after installing the new one.