Why are there so many gun models using the same calibre? Doesn’t the bullet determine most of the lethality and range, while the gun is just the vehicle that fires it?

Question

Why are there so many gun models using the same calibre? Doesn’t the bullet determine most of the lethality and range, while the gun is just the vehicle that fires it?

In: Physics

Answer 1

It’s sort of an idea that there are well established calibers out there like 9mm, 7.62, 5.56, 45, etc. If you want consumers to buy your firearms you need to make firearms in the caliber most people own. Then you get a piece of that market.