Available in .357 & .457!
 
We have been using these custom designed & machined billet aluminum M18x1 thread adapters for years on our Pitbull Airguns. They are now available as an easy install kit, wich includes the following:
 
M18x1 Threaded Donny Adapter
Drill Jig for precise drilling of secondary holes
Thread Protector Ring
Button head Cap Screws for Installation
Modified Stock Picatinny Rail (Optional, see video)
 
Features:
 
Four mounting points for rock-solid stability
Integrated Air Stripper
Black DuraCoat finish
Easy install 
 
Check out the install video above for complete instructions. An optional modified stock Picatinny Rail is available, ready to install.