I fitted the new style shoe as my steel piston liner was showing signs of wear where the shoe rests . Fitted a ptfe liner and gave the slot a very light debur. There seemed to be two fine high spots ridges running the length or the slot and the original bluing is intact along the middle almost like a u shape. There is a bit of scraping /wet sand noise as the shoe slides. Is it better to smooth this completely flat or just let the shoe find its way after a tin of pellets? Also if I were to flatten it out what would be the best way to protect the bare metal? I don't think a bluing pen be hard wearing enough.