The button on the 18650 model has a lock/adjustment feature. Turned all the way clockwise is locked, turned all the way anti-clockwise is auto-fire. It's probably the same on the 26650
I get that but didn't answer my question about the throw. The way it is only the very edge of the flat bolt will hit the battery because of the angle created.
Last - is there something newer as far as build instructions? I am using V1.1