Originally Posted by
Hsing-ee
If the piston seal is letting air past it, you can expect lower power, harsher recoil and poorer accuracy. I don't know if the 'dent' you mention is letting air past. If you put the piston in the cylinder without the spring, and hold your finger over the transfer port & press the piston forward with a dowel, you should get an idea of whether the piston seal is working well. Cuts on the lip of the piston seal can have a dramatic effect on power.
Maccari in the USA does a nice tuning kit for this rifle -
Usually takes a couple of weeks, but worth the wait. Price depends on exchange rate.
Spring and guides -
http://www.airrifleheadquarters.com/...488/552850.htm
Special piston washer
http://www.airrifleheadquarters.com/...485/945836.htm
good luck
Mr uk litehammer is well into Maccari for his air rifles which are top notch and he knows his stuff so it's got to be quality gear
John Darling JD (1946-2004) was my inspiration to be the best i can and enjoy the sport i love. R.I.P
A dedicated HW80 Fanatic and owner since 1986 to present.