Be careful what you watch on YouTube.
The bolt arm should fall off the front of the cam and not the side of the cam (as one guy espouses in YouTube vids.) Sliding off the side will only get worse for the cam, bolt arm or both.
The Jerry Kuhnhausen book (The Colt Single Action Revolvers a shop manual Vols 1&2). explains it very well.
Pettifogger is right about the Italian offerings having an integral cam. They can be removed and the hammer drilled for a conventional cam if needed. It's best not to "adjust" the cam except for the height. I adjust that on all my customers revolvers.
Lots can be done to restore a "too soon " bolt drop if it's not too early and you understand the procedure.
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