Well damn.. I just ordered one this ABR last night for my ax..
Adjustable Bag Rider - Adjustable Bag Riders
The Universal Rail Mounted ABR (Patent Pending) has been designed to mount directly to the lower picatinny rail with the supplied clamp and bolts . It provides the same functionality as the other ABRs with .920” of travel . Made in the USA from American 6061 Alum and finished with Class II Anodiz
www.adjustablebagrider.com