Ahem. I had a 30 Carbine for a while. The gun was simple but not crude, and enjoyably accurate to 100yds. It is easy for a small person to shoot. I never hunted with it. The deer had regulations forbidden 110gr low-energy bullets by then.
My opinions on the ballistic performance follow the counsel of the mainstream of gun writing that the Thirty Carbine was on the very low end of the spectrum of acceptible deer cartridges. I've hunted since then with 12ga, .303BR, 7.62x39, .30-06, .308 and .300WM, and never felt overgunned.
While there no doubt plenty of dead enemies despatched by .30 Carbine fire and the troops carrying the handy little rifles had confidence in them. The 20rd magazine is 2 1/2 times greater capacity than an M1 Garand. The BAR's is only 20rds, and had tremendous firepower for its time. In Korea, Canadians had bolt action rifles, BREN and STEN guns. It doesn't take much imagination to get all warm and fuzzy about a little self-loading rifle that has negligible recoil. As for others' writing on the Carbine's military effectiveness, I must admit to not having read (or remembered) many of US Army after action reports. As a firearm, it has plenty of fans, but that is not the same as liking the cartridge.
From Barnes' Cartridges of the World (9th ed):
-30 Carbine 110gr FMJ, 1900 fps, 882 ft/pds (with an effective range of 150yd )
-5.56x45 55gr FMJBT, 3250 fps, 1290 ft/pds energy (not a legal deer cartridge)
-32 Winchester Self-Loading 165gr SP, 1400 fps, 760 ft/pds energy ('strictly a small to medium game number at close range', 'a candidate for the title: "World's Most Useless Centerfire Rifle Cartridge." ')
-7.62x39 123gr SP, 2365 fps, 1552 ft/pds energy (a low power, but perfectly suitable deer cartridge)
In comparison:
-357 Magnum 125 gr JHP, 1450 fps, 583 ft/pds energy (which is twice as powerful as the same bullet in a .38 SPL)
-44 Magnum in a 20" rifle 180gr JHP, 1720 fps, 1580 ft/pds energy ('one of the few commercial handgun cartridges that can be considered fully adequate for big game hunting')