I asked about a new firearm in .30 carbine cartridge. Something more in the size of a an MP5/10 in 10mm for example to have more power than 9 Para, but keeping the small size. M1 carbines were very widespread, so was their ammuniton. Why has nobody designed a new gun in the same caliber as replacement? a full size AR-15/M16 is a rather long pole and can be unwieldy when used in a police car for example. Or inside a house.
The better is the enemy of the good enough? I´m currently reading "Misfire" and the author says the USAF wanted the M-16 specifically to replace the M1 Carbines. They liked the much improved lethality, better range, very flat trajectory and overall low weight(compared to battel rifles).