Modifying the Hatsan Quatro with longer screws is a dangerous procedure and should not be done unless you know what you are doing, and are willing to accept the consequences of your mistakes. It is not recommended by GTA. The Quatro is a very touchy design that is not forgiving of adjustment errors, and easily produces a random misfire condition when improperly/over adjusted. Also, filing material from the trigger blade accomplishes the same thing as installing longer screws and can result in the same problems.
Obviously you got one that has the correct length screws. When i pulled my 135th .25 mechinism apart, the screws when fully turned in barely crest the surface on the other side. Precisely why i filed the front surface down a 1/16". Without this mod(or installing slightly longer screws) the trigger adjustment feature is ineffective. The lighter trigger increased the accuracy tremendously. Of course proper care must be taken not to go to far....
The WTM is a rebranded 125.
Springer forever: Great News i think my mods have led me to similiar results on my 135th. How do you like the 155? Noticed the price has dropped(Pyramid) on the Hatsan Magnum Springers.Must be the start of clearing them out for the new gas jobs.