Ash:
Will measure if it helps but now seeing yours, I can say that the bead on my example sits right down on the base, ie very little blade beneath the bead, if any!
Bit pressed for time at the moment, but will take a pic if I get time, no promises...
Its possible that mine has a non-standard ramp of course, always a risk with firearms that have been in the hunting field for a hundred mango-seasons!
Hope this is of some help.