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

Rapid firing weapons have been a possibility for half a millennia but extremely hard to make happen until the last 150 years.

Only the relatively recent improvements in metal creation and modification have allowed for such weapons to exist in any major capacity and work reliably.