The article refers to many "other countries" where 3D printing is used to make firearms -- Myanmar, Spain, England and Ireland among them. In 1911, making a se

The article refers to many "other countries" where 3D printing is used to make firearms -- Myanmar, Spain, England and Ireland among them. In 1911, making a serviceable semi-automatic pistol or small caliber carbine was much harder than it is today. This was in part because the weapons themselves were comparatively complex in design; but also because the requisite manufacturing was harder to do. In the intervening years, the designs have gotten simpler and simpler. One way to baseline this is to learn about how 1911s are manufactured and how Glock 19s are manufactured. The Glock 19, a later design, is both much simpler to manufacture and more reliable than a 1911. Another thing that has changed is it is now dramatically easier to make the parts. Cheaper precision manufacturing, better quality and lower cost steel, power tools, 3D printing (useful not just for making frames but also for making jigs) -- all of these contribute to this. I suspect that a broad survey of countries in the 1800s would show that most of them had relatively widespread ownership of common small arms. It may be hard for us to imagine today, but England was one of those countries! The first act to restrict firearms sales in any way was the 1903 Pistols Act. From roughly 1900 until the 1980s, firearms laws tightened in the UK and many other countries. Now, relatively few countries have relatively ready access to semi-automatic pistols and rifles. From 1800 until 1950, let's say, we also say a great increase in the comparative complexity of small arms and individual weapons. The restrictions on the sale of firearms were effective because they stood between the manufacturers and the general public. While some of the manufactured parts are common place, hard to identify and even substitutable -- springs and pins and stuff like that -- many of them are not. They are easily identifiable and hard to make: barrels, slides, bolts, frames, release levers, extractors. In the decades following 1950, and certainly 1980, firearms have gotten easier and easier to make. I don't think this really reached a tipping point to where the restrictions on firearms sales were ineffective, though, with designs like the AR-15 or Glock 17. Changes to manufacturing technology had to occur as well, and many of those are quite recent, so I don't think your question is well posed.