Howdy
It is easy to blame our problems today on lawyers, but it is actually not that simple. Believe it or not, many of these types of devices originated with firearms designers, not lawyers, long before our present litigious society existed that blames restaurants for hot coffee, because it was recognized by the manufacturers that safety hazards existed in their products.
A good example is the lever trigger safety interlock on the Winchester Model 1873, that goes all the way back to 1874 or so. Winchester realized that the new rifle, with its more powerful 44-40 cartridge, would be safer if an interlock was included in the design, that would prevent accidental discharge if the lever was not completely closed and the rifle was not in battery.
Firearms designers had long been aware of the danger of the old Colt lockwork when a round was present under the hammer. When The S&W New Model #3 was released in 1878 one of the new features was a rebounding hammer that automatically wedged the hammer back about 1/8", pulling the firing pin away from a primer every time the gun fired. Unfortunately the parts were rather thin in cross section and I would not trust it if the gun were dropped on the hammer.
In this photo I am forcing the hammer forward to simulate the position of the lockwork at the instant a cartridge fires.
Once I let go of the hammer, the trigger spring wedges the hammer back slightly and the sear pops into a recess in the hammer that prevents the hammer from moving forward. You can see how thin the parts are and why I do not trust the rebounding hammer if the gun was dropped, I only load five in any old revolver.
Iver Johnson patented a transfer bar type of device in 1896, leading to their famous Hammer the Hammer advertising campaign.
When Smith and Wesson developed the modern rebound slide for the M&P Hand Ejector, Model of 1905, it incorporated the bump on the top of the slide that wedged the hammer back just as in the photo of the newer revolver I posted earlier.
Later, S&W included a 2nd, redundant hammer block in the design, during the 1920s or 1930s.
When a sailor was killed by a Victory Model striking the deck of a battleship during WWII the Government threatened to cancel further orders. S&W called all the engineers in and within one week had completely redesigned the hammer block to its present configuration, exactly as I posted earlier. Pretty amazing feat to redesign something like that and get it into production in one week.
All this happened long before the 'lawyers' started dictating the designs of firearms.
Of course, I find it completely understandable that Bill Ruger decided to completely redesign his single action line of revolvers back in the 1970s. He has suffered through enough lawsuits from families of shooters who did not understand how to safely operate an old fashioned single action revolver.
