If you look online, you'll find a tool to pull the FX regulator piston out of the action of the above rifles, and others I'm sure. It costs around $45 and is hard to find. Desperation being the mother of invention, I invented this tool to do the same thing. You can purchase it at Home Depot or Lowe's and make one yourself for around $5 or less.
It's really hard to make and you might need drawings and blueprints , but I'll just give you the rough idea, just in case I want to patent it.
Buy some 1/4" OD Polyethelyne tubing and it has the correct inside diameter to grab and pull the piston. Cut to the length of your choice and on the other end, take a knife and split the end, so that it will still hold the piston, and not drop it. Use the split end to insert the reg and push it home, and the split will let you easily work it back and forth to release the piston once in place.
It works like magic and costs nearly nothing and the PE plastic cannot damage the reg in any way.
It's really hard to make and you might need drawings and blueprints , but I'll just give you the rough idea, just in case I want to patent it.
Buy some 1/4" OD Polyethelyne tubing and it has the correct inside diameter to grab and pull the piston. Cut to the length of your choice and on the other end, take a knife and split the end, so that it will still hold the piston, and not drop it. Use the split end to insert the reg and push it home, and the split will let you easily work it back and forth to release the piston once in place.
It works like magic and costs nearly nothing and the PE plastic cannot damage the reg in any way.