Ode to the lowly M1 Carbine...

[INLAND44]

I've thought for years that the .30 Carbine round makes for the best sub-gun of any 'pistol' caliber. A bull-pup in .30 Carbine would be an incredible PDW. The Israelis had one they used for certain special outfits - the Hezi SM-1. You get the benefits of the small cartridge size (magazine capacity) and the larger, slower bullet (greater energy transfer and less over-penetration). I completely get why the M2 Carbine was developed; the mistake was in thinking it could replace the rifle in WWII/Korea tactical situations.