Thanks Boots, bought a 3mm thick sheet for $10.
Cut a piece and had to thin it with the bench grinder to fit in the Plunger (this was the hardest part).
Targets reset reliably every time now... They actually raise about 2mm above the stop every time now, so no more bad resets at start of game
I've added three pics, you can see the orig bakelite with the oval holes from wear, the sheet of Nylon, and the new piece fitted into the machine.
The only hassle was the thickness of the Nyon, I couldn't get around 2.7MM, it was 3mm only.
Boots - did you use 3mm sheet, if so, how did you thin it out (bloody stuff is damn hard)
So this Nylon stuff can be used to replaced all the worn bakelite for the plungers pretty quickly and have spare for Justin...