I think you meant to quote and respond to someone else...
Anyway, on my Colt SAA, it arrived with the safety notch broken away. Although looking at the photo posted by Driftwood, it would seem the trigger sear would break off first, I've read that it was common for the safety notch to break. This is dangerous as, in most instances, it would still allow the hammer to rest at that notch with the user thinking it was in a safe position. But pressing the trigger or jolting the pistol will allow the hammer to fall because the material that was intended to hold the sear in place in the notch is the material that tends to break away.
And, since the notch and sear are invisible to the user, and since no one looks anyway, how would the user know the mechanism is unsafe? The first accidental discharge, that's how.
I would guess that metallurgy in the late 1800s was not up to today's standards.
Darn right those plain carbon steels were inferior in every respect to the "same" steels today. The primary reason, in my opinion, is all the non oxidizing elements that were left in the steel. The steel furnaces of the day used air to burn out impurities. The air would combine with elements, but there are a surprising number of elements, copper, nickle, vanadium, tungsten, chromium are just a few that won't burn out. Given the composition of the iron ore varied based on where it was dug, the percentages of residual elements was unknown. And as scrap was dumped back into the kettle, the residual percentage increased with subsequent batches. This crap unpredictably, but always, reduced the strength and the lifetime of vintage steels. Sometime in the 1950's steel makers are using argon gas flushes, but not before.
A shooter brought out his Stevens M414 22 lr target rifle out to the range, and we smallbore shooter's ooh'd and aah'd over it. Still had some case hardening on the sides. The shooter, the rifle belonged to his Grandfather or Great Grandfather. There was a proof mark, a circle with a 20 inside, don't know if that means proofed in 1920 or not. According to one poster, these rifles were made from 1908 to 1932.
Good pictures of a Stevens M414 here:
https://bushcraftusa.com/forum/threads/stevens-414-22-rimfire-armory-rifle.144271/
Anyway, while the rifle was in excellent condition, the bluing was amazing and the wood was better than anything you find on the shelf today, the trigger had a crack extending into the receiver, just in line with the trigger pin hole. The owner just rolled his eyes and said that crack had been there for as long as he had been around. Which I guess, was more than 60 or 70 years, as none of us is spring chickens. That is the sort of stuff that happened with steels back then, they failed frequently and without warning, due to all the flaws, inclusions, and residuals.
Something that was true of the period, people just accepted dangerous jobs and dangerous products. Product manuals did not come with warnings. You were expected to know better, or you were expected to figure it out after you lost a couple of fingers!
Those were the days!.. How about a nice relaxing smoke with your asbestos pipe.
How about the lead that children were exposed to, on a daily basis?
I was given lead toy airplanes and figures from Depression era adults, things they played with.