They work quite similarly, it is simply which system won out with the buying public, though you are quite correct in that very few gunmakers have offered them in the last 125 years or so. I have owned quite a few over the years, several T. Woodward patent guns known as the "Spiral spring Woodward", a sidelock Lang and my most recent acquisition is a Grant, I just love the lines and uninterrupted top profile.

[Linked Image from i.imgur.com]

The drawbacks to a snap action gun in my mind are mostly related to the lever spring, it is shaped like a tea drop with the center removed and they tend to break occasionally. A complicated and costly repair but not the end of the world either. If you like them and find a good one I see no reason not to grab it.

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