Try the CZ 452 its exactly the same as the 455 only its a fixed barrel,because everyone is going for the new 455 you should pick up a 452 a lot cheaper, I got one about 3 months ago for £320, it loves hornady 17 grain and shoots very tight groups at 100 yards, if you want a .22 get a dedicated one, its saves a lot of messing about changing barrels and re zeroing plus they are cheap enough, you would still need an extra slot on your FAC for the extra barrel anyway.
Fair point, is the interchangable barrel the only difference?