my purchases with David at Alchemy have been very positive and it has been my experience that he doesnt make mistakes, at least with my orders, but it is possible? all you can do is send him a message and ask. if you are only interested in replacing it with an OEM valve and piston... order it from Crosman. it will be much cheaper and be correct for the gun without question. i switched to flat top valves/pistons and get them from Mellon Air, so dont know anything about the valves that Alchemy sells?1322A013, Valve assembly1322C020, piston assemblyif it is dumping all the air at 25 pumps, i still think you are dealing with a leak somewhere?
i understand how frustrating it can be. i am dealing with a similar issue with my upgraded FTP setups in both my 1322 and my 1377. i get 588 at 10 pumps with a standard valve setup and longer barrel, but only 589 on 1377 with FTP and same barrel length. the 1322 does a little better, but not by much. both are getting decent FPS and are both extremely accurate. i am going to pin the valve in my new build, test it, pin the valves on the other two and call it a day regardless of the results. its time to stop working on guns for me and start having fun with them. with your issue, its hard to know? it could be valve movement, it could be something else? it sounds like you have covered all the bases with possible leaks as a cause, and with a new valve in place, unless maybe you put the transfer port back in upside down... i honestly dont have any other suggestions.