I do know that a 9mm in a 40 Glock leads to humorous results. A husband/wife duo found out when the husband grabbed up some loose rounds from the bottom of the range bag to load his 40 (wife shot 9) and some of her rounds had gotten mixed in. What sounded like a squib load was the entire 9mm round about halfway down the barrel.
I believe you can put 22/23 magazines into a 19; you can build a Polymer80 frame, for instance, for 9mm, .40S&W or 357 SIG and the only real difference is the ejector. (And even that doesn't seem to be a very big deal most of the time.) I think the only real dimensional change as far as internals, is when you go up to .45ACP or 10mm. That's a different frame size.
You can also chamber a 9mm into a 40S&W, and it *might* "headspace" by being held to the bolt face by the extractor. It might even fire. Probably wouldn't hurt anything from what I've read (although I would not suggest trying it), but the ballistics would be, ah, degraded at best.
My poor Dad, in the dark, bear getting into his beehives, ran out barefoot in his skivvies trying to load his revolver. Turns out 9mm rounds just fall out of a 44 magnum chamber. Mom had handed him a handful of the wrong ammo as he went out the door.
I do know that a 9mm in a 40 Glock leads to humorous results. A husband/wife duo found out when the husband grabbed up some loose rounds from the bottom of the range bag to load his 40 (wife shot 9) and some of her rounds had gotten mixed in. What sounded like a squib load was the entire 9mm round about halfway down the barrel.
I believe you can put 22/23 magazines into a 19; you can build a Polymer80 frame, for instance, for 9mm, .40S&W or 357 SIG and the only real difference is the ejector. (And even that doesn't seem to be a very big deal most of the time.) I think the only real dimensional change as far as internals, is when you go up to .45ACP or 10mm. That's a different frame size.
You can also chamber a 9mm into a 40S&W, and it *might* "headspace" by being held to the bolt face by the extractor. It might even fire. Probably wouldn't hurt anything from what I've read (although I would not suggest trying it), but the ballistics would be, ah, degraded at best.
My poor Dad, in the dark, bear getting into his beehives, ran out barefoot in his skivvies trying to load his revolver. Turns out 9mm rounds just fall out of a 44 magnum chamber. Mom had handed him a handful of the wrong ammo as he went out the door.