Thanks BYD! Tank valves I get on Ebay, if I need one quickly, Amazon. I have all the belleville washers to adjust them if I need to. The Avenge x 177 isn't choked, but it's a snug bore, doesn't allow the pellet to fumble around. Not like the Avenger barrel, huge heavy choke. I have another X barrel in .22, haven't got the specs on it yet.