Thanks Bob, I can see why the sear needs a good fit and when done properly I'm guessing that type of sear set up reduces the torque making the lock real smooth.
The main advantage is the full cock notch doesn't have to be any deeper than a good scratch.
I use .1094 polished drill rod thru a REAMED .110 hole. The sear is relieved or "ghosted" on the
back side. The torque is supplied by the mainspring and the link that hooks it to the tumbler.
Making this style of lock is more labor intensive than the mechanism shown in the J&S lock
but the J&S as I made it is better than the old ones from Goulcher and others of that time
period.Few old American guns had a quality lock and if they do they are usually on a target
rifle from the New England states such as N.G.Whitmore from Potsdam,NY.
Bob Roller