[TXnMA]

The head diameter of the .380 is smaller than the 9mmP,

The (rimless, in both cases) head of the .380/9mmKurtz/9mm short/9X17 case is definitely smaller than that of the full-sized 9mmParabellum/9X19 case.

In fact, here is a useful bit of trivia: the base of the .380 pistol round and the .223/5.56mm rifle round are basically the same -- they use the same baseplate for reloading.

How does that make you M-16/AR-15 fans feel -- to recognize that your rifle's case diameter is the same as the relatively puny .380 pistol cartridge...? ;-}

[Myrddin]

How does that make you M-16/AR-15 fans feel -- to recognize that your rifle's case diameter is the same as the relatively puny .380 pistol cartridge...? ;-}

The volume of 748 powder pushing that puny 55 gr spitzer makes up for it :-) 3150 fps makes for some serious muzzle velocity.

[Lurker]

“How does that make you M-16/AR-15 fans feel — to recognize that your rifle’s case diameter is the same as the relatively puny .380 pistol cartridge...? ;-}”

Considering that a 5.56 mm bullet has as much energy at 100 yards as a .45 ACP does at the muzzle, not too bad. Why?