I have found that I cannot put the proper angle on the bevel with the KME knife sharpener if I leave the blades in the ferrule, so I take them out. The ferrule on the 150 grain Stingers is bigger than on the other Stingers which makes that broadhead tougher and better, but it makes it more difficult to sharpen with the KME system, which is the one I think does the best job at home. To sharpen the Stingers (and many other broadheads) in the field, I use a Redi-Edge Sharpener, which works well without removing the blade.
Allan