Hello All
I've been making my bump keys with no shoulders for some time now. I do this for several reasons. B=It allows you to use springs for rapid automatic 'resetting' - a technique we're calling 'bouncing (vid below)
And also so you can add 'dampeners' - washers of various materials and sizes which allow you to position the key exactly where you want it, from the follow through, swing and clip or even the minimal movement method. The addition of these tools allows you to exploit more variations in the locks and cause different responses in the keys and there fore pins.
Anyway, enjoy the videos, they're pretty poor quality but you'll get the idea. I've used the (notoriously) difficult to bump UNION locks in the 'dampener' vid to illustrate my point. Click them to watch
click for spring bumping 5 locks
click for 'dampeners on' UNION bumping
regards