Air Arms TX 200 Adjustable SS Piston Rod
TX 200 Adjustable piston rod with extra long threads for a lot of adjustment to get the maximum stroke. This is made of Stainless Steel.
TX 200 or Pro Sport Piston
To Make the piston adjustable.
Remove the rings and washer.
Measure the distance from the skirt to the groove where the piston sear engages, and write it down. This is so you can set the new one to this as a starting point
Hold the piston rod in a soft jaw vice.
Heat the top of the piston where the rod is threaded into the piston, this is to break the Locktite.
You do not need to get it really hot. So do not get it so hot that it starts to turn blue.
Once it is hot enough you can grip the bottom of the piston with heat proof gloves or similar and try to unscrew.
Replace with the adjustable rod to the distance you had measured previously. Reassemble the gun and check that it cocks.
You can use a weak spring to test that the gun cocks.
Now that it cocks unlock slowly and take the piston out again. But now screw the rod in a couple of turns and check it cocks again. If it still cocks then take it apart and turn in the rod another turn until you find it will not cock, when this is found you know that you have to unscrew the rod to the previous setting before when it did cock. This is maximum stroke that that gun can do.
Measure again and count the number of turns so you can put Locktite on it for final assembly.
When you have tested and are happy with the setting then you have to cut the front of the stud off and file or machine it flush.