So I've read alot online about Weihrauch springers benefiting from having a Teflon (PTFE) piston liner installed. Most of everyone swears that a 0.5mm thick piece is perfect. I went ahead and ordered 2 full sheets. One of 0.25mm and another of 0.5mm. I have not yet installed one in my hw97k yet, but will be doing so very soon. I just want to get measurements first so that i can turn myself a new tophat as well. I'm pretty sure they are going to make a huge difference together in the shot cycle and overall manners of the rifle. I have already added my own design tophat to the TX200HC and it has made it sooo much nicer. Anywho, I'm going to have quite a bit of PTFE left over, I'll be selling it off if anyone is interested, PM me. 300mmx300mm pieces.