Well, got a reply from ARH. Pretty much what I expected. The seals are what they are, the inconsistencies in Hatsan piston heads and air tubes are just too difficult to make a production part for. I may try a Vortek seal, and will also likely order some stockers from eBay (since Hatsan doesn't seem to have any, at least not on their online site), or maybe even one of those Australian ones (they supposedly measure 27.20mm). In the meantime my 85 is shooting better than it ever did with the ARH seal, and the Webley is really starting to shape up as well. I would just leave those seals in them if I didn't already see with my own eyes how battered they are.