My RAW HM 1000 lost accuracy once, and the maker said it was probably a dry or dirty hammer, and recommended cleaning and lubing with a synthetic motor oil. I did as directed and it fixed the issue. I've been using Mobile 1 synthetic oil and grease on guns a while now, and it seems to work well. Compared to specialized air gun or firearm products it's dirt cheap too. Guess time will tell regarding its durability.