I would guess the stock can be slid down to the bottom of the hilt or removed completely?
Sliding the hilt into a hand hole and attaching the stock to the protruding hilt seems like the idea to me.
The hilt looks just about long enough depending on the particular figures hand it is used with.
The Mech iDeas version looks like you are holding a magazine rather than a hilt!
I wonder if the good Dr will also give Shockwave a go too?
ROBOTMEL'S WANTS LIST! PM ME PLEASE! Classics/Generations - 25th Ann Unicron, YotS Omega Supreme
Alternity - Ultra Magnus, Dai Atlas, Saber
IDW Transformers (2009 Ongoing) - #22b (VF/NM)
MARVEL Generation 2 - Halloween Special (VF/NM)