Its for piecing the pie and looking around corners/door frames.
When you put it at the angle, you can get so close to the corner of the door, that your head just barely pokes out. Now try it with the stock in the normal position and a lot of your head and shoulder is sticking out too.
You can do it pretty well with the stock "upside down" for lefty-shooting too.
You cant use iron sights in that config, but indoors stuff is so close range its not a big deal.
Any documentation/source for this?
























































