I've had an "early" CZ452 Varmint and had a difficult time getting it to shoot well. I finally free-floated the barrel and bedded the action. That made all the difference, but it wasn't the rifle for me.
A a year or so ago, I bought a new/used CZ455, .22WMR and it had problems that I corrected, including bedding, firing pin shape, and trigger pull. It now shoots MOA at 100 yards with the right ammo, but with other ammos varies from 1 1/4 to 3 MOA. I was immediately attracted to the woodgrain of this rifle and apparent newness in the used gun rack. It's lightness and accuracy make it my favorite walk-about rifle.
The 455 is a switch-barrel design, but because I never intend to shoot either .17 HMR or .22LR in it, I LockTite-d the barrel in with Steeve and Bearing Mount. It worked for my Ruger 10-22, and seems to have helped the 455.
People are like rifles. Some are tried and true, having great eyes, personality, and fun to be with. Others never seem to hit the mark with you. Still others go off half-cocked. Still, it's nice to know most of them.