eli5 Why weren’t machine guns possible to make in the past?

Question

What stopped 18-19th century armies with guns from being able to create automatic weapons like AK-47s and Uzis?
Since they don’t use electricity I feel like they’re made with materials and technology that was already available in the 1750s, surely they could’ve put their heads together to create a machine gun and just annihilate any ops…

Thanks

In: Engineering

Answer 1

Self contained cartridges were needed to have machine guns that could reliably feed from a magazine or belt. To have self contained cartridges it requires machining hundreds of thousands or millions of cartridges to exacting specifications (off by fraction of millimeter = explosion). Once machining advanced to the point where cartridges and weapons could reliably be manufactured, automatic weapons followed very shortly.