Over on Rimfire Central's CZ forum, where there are a lot of folks posting about their CZ rimfire rifles, the general consensus is that there is little, if any, difference in accuracy between the 452 and the 455. To be sure, there are examples of "lemons" in each model, but they are the exception; the CZ is, after all, a mass produced sporter rifle. The main difference between the 452 and the 455 is that the latter has a common receiver and can switch between any 455 barrel configuration e.g. sporter barrel, bull barrel, barrel with sights etc. in any caliber -- 22LR, 17HMR, and 22WMR. I have a 455 Varmint with barrels in 22LR and 17HMR.
The 452 has ostensibly been discontinued, although there have been some recently-minted rifles making it to the U.S. and to Canada. Reliable Guns (a CGN sponsor), for example, has had some CZ 452 Americans with beech stocks (which may have been originally destined for the Australian market). The 452 rifles have non-removable barrels (non-removable by the everyday user), so with this model, it remains in whatever barrel configuration and caliber it comes in. Certainly one part of the appeal of the 452 is that they are becoming increasingly harder to find. There will be a time when no more new 452's are available.
I have two 455's, and one 452 American (with the beech stock but purchased new locally in 2014) and a 453 Varmint. The 453's are similar to the 452's with a fixed barrel, but they have a single set trigger, which basically means it has one trigger with a very light setting for shooting off the bench and a heavier setting more suitable for hunting. The 453 set trigger is operated by simply pushing it forward for the lighter pull weight setting. My 452 and 453 shoot better than the stock 455's. If I was looking to buy a CZ rifle today, either new or used, I would buy the 452 if I could. If not, I would buy a 455 and would recommend them to a friend.
