I've never seen one, but they look cheap to me based on the YouTube vids.
I already made the mistake of trying to get it done while saving a few bucks and I barely have mine sighted in and realized it was a mistake. (mistake for my needs... great rifle for hunters and plinkers)
I just want what will work for me the first time without going through a bunch of costly mistakes to get there in the end.
Besides... for my needs it needs to fit into an aftermarket tactical PRS style chassis (like Aeron or Jet Air) and I'm not aware of one for the HW110.
https://scandinavianairguns.com/shooting-gear/jet-air-chassis/