Tommy... it's part of the history/evolution of the Magnus I.
Originally Mike Sohm slotted Zwickey Deltas to accept a bleeder blade. I'm not sure of the exact process, but that's what he did.
Side note... at the same time Fred Asbell down in Colorado was doing the same thing, which is where I got my first broadheads of that style.
I don't know if Fred thought it just wasn't worth it or what, but when he found out Mike was doing it too, he started just getting the heads from Mike...and so did I.
There was a little squawking from Zwickey aimed at Mike Sohm who eventually started manufacturing the whole broadhead... making it slightly larger in the process.
I worked very closely with Mike in the early days and watched the broadhead line evolve.