I think the title of the thread does not reflect the actual OP concern, which is not the travel of the key per se, but how to avoid bottoming out. Again, the point is not the geometry, that may somehow altered adding O-rings, or dampeners, but the force against the fingers during typing, so it leads again to the springs, that are what the switch has as a way to get it to its original position, and that produces the force for the user to type on. Module of the springs depends on size, coils per length, and wire module. In theory you can get any force within a range, using the same overall length of the spring, and the same diameter of the coil, modifying the coils "density" and the wire.