Okay.
To declutter this a bit, because the "NOT A GUN PEOPLE" are, I think, confused and there are two conversations going on.
The term "pistol" refers to a handgun with an integrated chamber and barrel, such as a "semi-automatic pistol" while "revolver" are refers to a gun with a revolving chamber.
Semi-automatic pistols and Double-Action revolvers both fire one bullet per trigger pull, without requiring you to manually cock the hammer each time. (SR just calls both "SA" even though it can cause confusion. Kind of like now.)
SA pistols and DA revolvers are very common. They are not rare, either one. The SA pistol has been around since the 1880s, and the DA revolver since 1851. They are, respectively, the 1st and 2nd most common types of handgun.
To be clear, my comments are for clarification purposes - I realize not everyone knows, or cares. But SR has always been willfully ignorant when it comes to firearms, despite the prominence of guns in the game, and that combined with a "NOT A GUN PERSON" can become awfully confusing when people use terms incorrectly.
TLDR: What you said was kind of puzzling, even if we take into account that what you said isn't what you meant.
-Jn-
Ifriti Sophist