can you switch up barrels on a r9 very easily?

[CHUCKMATLOCK]

Is it possible to just buy a barrel in .22 cal and switch the barrel and the locking mechanism? I am not exactly sure what it is called but can you purchase the barrel already mounted in the block and just remove the screws and reattach a.22 barrel and block or will the breach seal not match up correctly?  by the way does anyone know if Charlie works on Beemans?

[CharlieDaTuna]

and yes, some of them.