As a side note:
I have heard of folks loosing the end of the arbor after doing this type of thing. The reason is because of the arbor being too short (as Mr. Hawg mentioned). You see, this is something you would do to enhance a short arbor fix.
If there is room at the end of the arbor hole for the arbor to stretch, it will. Even to the point of breaking. If the short arbor has been taken care of ( now dead ends into the end of the hole), the arbor has nowhere to stretch to, allowing this adjustability for the wedge.
I post often about this very set up but it is in conjunction with the arbor fix. Once the set up is done, the vibration travels through the revolver as a whole. If a space were still available in the arbor hole, it would interrupt the transfer and that's when bad things happen with open tops.