I'd not even considered twist rate when I bought the rifle, as I reload for other .223 rifles with rates 1:11, 1:9, 1:8 and 1:7, and generally speaking the Berger 55gr FB Targets can run in all of them very well with a little variation in charge. The odd exception is the 1:8 ER Shaw barrel where anything less than a 62gr BT seated right up to the lands is likely to keyhole. I've had the best luck with 70gr VLD BTHP out of the 1:9, and 1:7 twists.
According to Wikipedia all varmints from 2002 on were 1:9. According the CZ site the barrel for the 1:12 Varmint should be 25.6". Even the Euro Varmint is reported to be 25.6"
This barrel is 24". Could this be a grey laminate varmint that left the factory with a walnut stock?