Cz 452

The 452 is threaded so no drop in available. You would have to order a blank and have your gunsmith chamber, thread, crown, and install it. Depending on who's blank you choose and the smith you use, your looking at around $500-$700 for a match grade barrel with install.
 
Looks like CZ may be phasing out the 452 in favor of the 455 for that very reason. I have a 452 Varmint in 17HMR I bought several years ago and its listed as "discontinued" on thier web site. If I were to start over again, I'd get a 455 - the idea of aftermarket barrels is very appealing.
 
I rebarreled a 452 with a Lija threaded barrel and restocked it on a Manners stock. Yes the price adds up but it shoots better than before. I have several 5 shot groups in the .1s and lots in the .2s with Eley tenex. With other ammo it shoots more like .3s. I just posted 6 consecutive 5 shot group avg on the 22 thread above at .258. Picures are on the last page of the thread. The rifle shot well before but better now. John Whidden rebarreled it and I am sure he would do you one too if interested.
 
I was hoping to trick it out into another trainer but I probably should leave it alone, its the 452 Trainer and it shoots like a laser with the irons sights it has.
I'll just pick up a 455 sometime and make that my new tinkering toy. Already have a Savage set up in a Rhineland stock that is good enough for what I want.

Thanks All