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

Modern machine guns require predictable ammunition, the escaping gases are the thing that pushes the bolt back to allow another cartridge to feed. Early gatling guns, which were fielded in the mid 19th century, required a man to crank the thing. Once the ammunition became much more standardized and well manufactured, automatic reloading weapons weren’t far behind. Like, the 45 ACP (automatic) was made to work with the M1911 which uses a short recoil action was also used in the Thompson machine gun which is blowback operated.

So, the TLDR is; the ammunition.