So, a guy with a brand new permit to purchase handgun is still shopping. He knows he is ignorant, so he asks questions of me rather than going to a gun forum or summat. The new LCP came up and he asked if it was 9mm, and I went PURE PEDANT on him. But in a good way. No really.
I remember when I was plug ignorant on the subject, here, and how becoming less ignorant was kinda neat. But I was flying blind and typed this up from memory, not even a wiki search to be sure I didn't confuse sumthin.
No, it's not what you are thinking. Not 9mm NATO, aka (for the most part) 9mm Luger.
The LCP shoots the 9mm Short, aka the 9mm Kurz, aka the 9mm Browning, aka the .380ACP. ACP = automatic colt pistol. Two different rounds, with lots of names for those 2 things
The first one has a case a little bit longer. That's the only difference. Other than little bit of brass they cram a lot more propellant in there so the pill goes a lot faster.
You know what has an even LONGER cartridge case and the same size bullet? That .38 Special. But the .38SPL is much 'weaker' than the 9mm Luger. There is room to cram more powder in a .38, but they don't. Not and still call it a .38. Old guns would become hand grenades if they did. NEW gun that only expected .38 Special pressure would too.
But, if you crammed more powder in there and made a gun that could handle the pressure... Maybe made it a trifle longer only so that you couldn't accidentally load this hot new round in a weaker old revolver... Then you'd have a .357 Magnum.
The light went on over his head. He understood more. And didn't lead him too far astray with BS.