The HP is by the wayside? Huh.
Just a gnat's worth of difference between a Zipper and the HP. Better bullet selection would be a driving factor to go with the Zipper though.
People without a sense of aesthetics shouldn't be allowed to do gun work. This guy may just have been simply drunk when he made that stock, or tripping on peyote.
I bet he was stumped by the old "how do I make a straight lever work with a pistol grip" rhubarb. "Never mind Bunkie, I can make it work."