GAMO makes a barrel mount that fits into the 3/8' dovetail grooves on the original barrel. The accessory that they sell has three tightening screws and a recoil hole with 3/8" dovetails that run the length of this accessory. I'm not sure how long it is but I imagine less than 10" and more than 5" - I'm guessing from the picture. GAMO suggested I buy one ($15) as the recoil on my Wildcat Whisper has elongated the recoil pin hole and this would replace the recoil hole that has been deformed. I'm sceptical. Has anyone used this and does it work well?