I have a CZ 452 in .17 Mach 2 caliber that I absolutely love...problem is, seems like it is a dinosaur caliber that I am not going to be able to get ammo for much longer. CZ has fixed this issue on their new CZ 455 rifles and made the barrel changes process something the common shooter can do...well, this is not the case with my CZ 452 and I have a couple of questions about what my options are as far as changing out barrels once I run out of .17 Mach 2 ammo I now have and they no longer make it. 1) Can I have a gunsmith change my barrel to a .17 HMR, .22 LR, or .22 Win. Mag. or maybe even change it to a .204 Ruger? This way I can at least still use my rifle since it really is a great little rifle. 2) Better yet, if I stay with the rimfire calibers, would it be possible to get a gunsmith to make it where I could have a barrel in more than one caliber and change it back and forth as I choose like with the new CZ 455 rifles? Thanks for your help.