As I have said over and over, this great little gun has plenty to love as-is, and thanks to its particular form and construction it can easily be modified with very simple after-market parts to bring it up to 21st century currency.
And as for the prime objection to the .30 Carbine as a fighting cartridge:
During its military career, the .30 Carbine was considered by many to be inefficient at stopping the enemy, especially when compared to the .30-06, which offered a lot of penetration and energy. Stopping power was really criticized during the Korean War where the enemy — often hopped up on stimulants — was usually wearing bulky, cold-weather clothing.
However, the ballistics of the .30 Carbine are surprising — the standard military round with a 110-grain bullet at around 1,900 fps generates about 900 foot-pounds of energy. This is better performance than the .357 Magnum, which is an excellent choice for defensive purposes. The problem back then was the FMJ ball ammo used by the military, which basically punches right through an adversary without expanding or fragmenting. Choosing the right ammo is the key to defensive effectiveness, and modern designs with expanding JHP bullets will perform nicely. Some examples? Federal has a 110-grain JSP Power-Shok offering that has an average velocity of 1,990 fps. Hornady offers their FTX version of the .30 Carbine with a 110-grain Flex Tip bullet at 2,000 fps. According to their specs, this round delivers 15 inches of penetration in ballistic gelatin, which provides enhanced stopping power.
It’s a fine choice all-around, and a neat piece of American military history.