Thanks Deerslayer303 and Dave!!
In fact, every S.A. can use a stop. In this case we are talking about Italian reproductions which are of the Opentop design and employ a one finger hand.
When the bolt "drops", that is when the left arm falls off of the hammer cam and the bolt head or ball comes into contact with the cylinder. In a correctly timed S.A., it should meet the cylinder in the approach ( also called a " lead" by many) about a bolts width from the locking notch. This is the second click in a Colt / type opentop, the third click in a S.A.A./ or reproduction of . The last click (when cocking to full cock) in any of the above revolvers is the bolt snapping into the locking notch AND the sear engaging the full cock notch on the hammer simultaneously.
This being the case, with the linkage/clearances of parts involved, the hammer can be pulled back to differing degrees after lock up of the cylinder. I've done many Colt opentops and every opentop and Remington that leaves me has an action stop. If no stop is present, the only thing stopping the action IS the locking of the cylinder. This is undue wear of parts such as the hand, cylinder ratchet, locking notch and added pressure againt the bolt and it's screw pin holes. This last thing is actually eliminated with the installation of a bolt block which is also in every revolver that leaves here.
So, the cocking "range" is from rest to the sear/full cock engagement. Everything has to happen within that motion. With the Mod. P reproductions that I own/have owned or worked on for others, none have had the "range" end with contact of the back strap. If I remember correctly, this is the same "range" outlined in Jerry Kuhnhausens book on the Colt Single Action. No mention of the back strap being the limiting factor.
Hope that at least explains where I'm comming from on the subject Jim K.
The bolt block and the action stop are what gives me the confidence that the tunings I do will last. In fact, any cylinder play/clearance a cylinder has at rest is the same as when the hammer is at full cock with your thumb still pulling back on the hammer (proving no hand pressure againt the ratchet). That wont happen in a revolver without a stop.
And, a stop was actually designed into the Mod.P (the large boss at the pivot pin on the hand was supposed to contact the web between the hammer slot and the hand as a limiter). This is a main reason that I DO install stops in all S.A.s . (even Colt thought it should have one!)
Mike
www.goonsgunworks.com
I just looked up in the referenced book by Jerry Kuhnhausen and on page 223 found " Make sure that the hammer moves freely in the backstrap slot, at D, and rotates to full cock position without hitting or stopping on the backstrap".
The true stopping point in the single action is the hammer/sear engagement. There is no need for further movement.