First one is a "safety notch"....meant to catch the hammer, should your thumb slip off while cocking the gun.
Second one is the loading/unloading notch. You can also note that due to it's shape, the trigger can not be pulled while the hammer is in this position....unless you use enough force to break the notch and/or shear the sear-edge of the trigger.
Third click is the latch (AKA bolt) being released back onto the cylinder via spring pressure.
Fourth click is the sear engaging the full cock notch on the hammer.
If you hold the (unloaded) gun up to your ear while you cock it real-slow, you'll probably hear 5 clicks. That's because most all SA revolvers are/were shipped slightly out of time....and the one's that weren't have gotten that way over the years.
If that is the case with yours, just look at the bright side.....
"They" say that 4-clicks spells C-O-L-T. So if that is true, I'm saying that 5-clicks must spell R-U-G-E-R. :wink: .
Not usually. With a lot of single action revolvers the hammer goes to full cock a teeny bit before the cylinder locks up. But it is usually only detectable if the gun is cocked very slowly. In normal operation when the hammer is cocked vigorously the hammer goes to full cock but has enough over travel to shove the hand a little bit farther, which shoves the cylinder around the tiny bit needed to allow the bolt to pop up and lock it in place. In a perfectly timed revolver both of these things happen at once, but it usually is not a problem if the hammer goes to full cock just before lockup.
The problem occurs the other way around, if the bolt pops up and locks the cylinder before the hammer has gone to full cock. In this case, once the cylinder locks, the hand can wedge and prevent the hammer from travelling back the rest of the way to full cock.
So if the hammer cocks just a teeny bit early, it is better than it cocking a teeny bit late. Very few revolvers leave the factory with perfect timing.