I know Danny Biggs came up with/has something similar or maybe even exactly...and of course Dan Bramley. These are the two I personally know of, there may be others.
Two years ago Dan sent me the instructions on how to do this stock modification,,,honestly it was above my pay grade and I took a different stock route. I can appreciate having the opportunity to shoot the finished version of this style of stock without having to butcher a couple getting from point a to b.
