That's because none are timed as well as the particular Kimber you own. All could/can be just as smooth.
These M70 style safeties have a small cam on the inside. This cam engages the cocking piece and has to move it back ever so slightly to hold it off the sear. The angle at which the cam on the safety meets the cocking piece are cut by the installer, This cut also determines how far the cocking piece is pushed off the sear. These all determine how smooth the safety is, going from fire to safe. Also, there is a pin that slides out of the inside of the safety shroud that locks the bolt when the safety is all the way back. If the channel in the bolt body isn't cut right, this can cause problems too and will affect the smoothness of the finished product.
If you took every safety you owned off the rifle they will all feel the same when you operate them. When installed they all feel different. It's because the different feel comes from the contact with other parts and how they mesh together. Installation is a MAJOR factor in the finished product.
Terry
