The shop where I work recently had two new Uberti SAA revolvers for sale. Neither of them had the half-cock notch when the hammer was pulled back. I think they may have gotten rid of it...
“The shop where I work recently had two new Uberti SAA revolvers for sale. Neither of them had the half-cock notch when the hammer was pulled back. I think they may have gotten rid of it...” [Galatians513, post 88]
The Uberti arms you encountered may have been marketed as new, but they could have been damaged, worn (represented as new), old stock (before blocks and transfer bars), or tinkered with. Anything can happen in “the trade.”
The hammer of a Colt’s-style Single Action is massive. Driven by very stiff mainspring, in falling it can break off the trigger tip, or snap the overhang on the safety notch and the loading notch, and drive the large rigidly fixed firing pin into the primer of a live round.
The likeliest explanation is that Alec Baldwin reflexively stuck his index finger into the trigger guard when he drew the revolver. It touched the trigger firmly enough to drop the cocked hammer, or to hold it back far enough that the hammer fell from the full-cock position when his thumb turned it loose. Same result.
Thanks to sloppy gun handling shown in scores of films and TV shows, most folks are sure they know how to handle Old West firearms, but they don’t. Fingers slip into trigger guards as if they were born to do it. Reflexes have to be untaught, then re-programmed into the moves that safe safe gun handling. Hence the rule, Keep the finger out of the trigger guard until on target and ready to fire. Constant vigilance in the field, on the range and during classroom instruction is highly recommended.
Not all single actions are made the same. Colt’s percussion revolvers had but two intermediate hammer positions: the loading notch, which lifted the bolt to allow the cylinder to freewheel (forward only), and full cock. “Safety” was handled by tiny pins between chambers, over which a recess in the hammer face could rest, immobilizing the cylinder.
Faced with lawsuits over sloppy handling of their old-style single action revolvers, which operated pretty much like Colt’s Single Action Army, Ruger engineers built in a transfer bar attached to the trigger, and linked the bolt-lift function to the loading gate. Makes for a one-click hammer function: full cock only. It’s been incorporated into all New Model Ruger revolvers. These arms may be safely carried with a full cylinder - six (or seven, eight, or ten as applicable) live rounds, in safety as good as that of any modern double action.