"After you cock the weapon, the bolt should drop. This allows the cylinder to rotate when first/top step of the hand to engage the cylinder ratchet. Further cocking allows the second step of the hand to complete the cylinder's rotation. Before the hand finishes rotating the cylinder such that it is lined up with the bore, the bolt should pop up and arrest any further rotation. The hand then finishes the rotation and the hammer has reached full cock."
The later Colt Single Action Army (1873) does have a two-step hand, but the earlier cap & ball revolvers (including the 1860 Army) does not.
If the bolt pops up and "arrests" further rotation, the hand cannot rotate the cylinder any further unless it overpowers the ball on the bolt that has lifted into the cylinder's notch.
If the revolver is timed as Colt did it during the mid 19th century, the tip of the trigger will drop into the full-cock notch at the same time the back of the hammer hits the top of the backstrap. At this time further rotation of the hammer is stopped, and intentionally so. That said, these days this is seldom seen.
Then the point (top) of the hand is adjusted to that it will turn the cylinder from one chamber to the next, but no further.
Last, the bolt is fitted so that it will start dropping down as soon as the hammer it started backwards by thumb-cocking and released to pop up just short of the next notch in the cylinder, with it (the hammer) reaching full-cock.
If the hammer rotation is not stopped by the backstrap and the point of the hand is too long it will try to over-rotate the cylinder, which cause strain and battering of the hand, cylinder ratchet tooth, and cylinder bolt notches. If the bolt spring is weak or broken the bolt may jump over the notch.