Don't want to sound too picky here but a little on lock terminology. Flintlocks normally had a half-cock notch. This was about midway of the travel of the tumbler & was generally necessary for the flint to clear the frizzen so it could be brought into battry prior to full cocking & it did serve as the safety as well. With the switch to percussion the "Half-Cock" notch was most generally done away with & a Safety notch added in with the hammer in a lower position which did not contact the cap, but also did not give enough clearance for the cap to come off the nipple. Early breech loaders for the most part retained this Safety notch position rather than a half cock. Both these notches were almost always undercut for the sear nose to prevent pulling the trigger while engaged. On a rebounding hammer there should still be a safety cut in which the sear nose prevents the hammer from being pushed into the firing pin unless the trigger is pulled. It is however not undercut. The trigger can be pulled from this position but the hammer should not move as it should be rebounded behind this notch.
The Colt SAA revolver had both a Safety Notch & a Half-Cock notch as well as the full cock. You can pull the hammer back slowly on the Colt & hear 4 clicks. 3 are the sear falling into the various notches & the other is the locking bolt clicking up against the cylinder. I realize this is a mere technicality, but "Most" post flint-locks did not have a "True" Half-Cock. A few did.
