I checked with Daisy first thing. They don't carry any parts for the 7xx series. They gave me some names of places to check but nobody on the list had a 722 barrel assembly or separate housing for the valve. I found a .177cal 717 barrel but not the .22cal. I checked Gun Parts, Ebay, and Gun Broker also.
Daisy sells parts for the 717. All parts are the same except the barrel and the side plate with the "722" markings. I have been told that the .22 barrel has been discontinued. They have no parts list for "722" and confuse it with a rifle model "722x". The form is current and the phone number on it is correct.