Oh. I was imagining some dumb crook with a hodgepodge of ammo thinking (or not thinking) that any wrong, randomly-selected ammo would somehow fit his gun.
hah ... Some of ‘em are so dumb they might do that if it were physically possible ...
Aside from stuffing a .380 ACP cartridge in a 9mm mag, I’m hard pressed to think of an example. The .380 would probably feed but would not fire.
Now ya got me thinking ... 9mm in a .40 mag? .40 in a .45 mag?