M2 vs. M1928M1

[Seaspriter]

contrary to popular belief is a short rifle cartridge, not a pistol cartridge as so many have asserted

You are absolutely correct in this. However, the short rifle cartridge (.32 Winchester from 1905) never took off, it was quite underpowered.

From a physical comparison, the .30 carbine is comparable to a .357 Magnum or .38 Special pistol cartridge, and smaller than a .45 Colt, the biggest difference being the latter cartridges were for revolvers. For the fun of it, put all four of these side by side, then along side a .303, .308, .30-30, .30-06, and it's easy to see why .30 carbine is thought of a pistol cartridge.

Put another way, compare case capacities:
- Compare the .357 Magnum (also developed in the 1930s) to the .30 Carbine -- about the same. The bullet weight of a .357 Magnum is 125 grains compared to 110 grains of the .30 Carbine.
- Compare the .30 Carbine's case capacity (1.364 cubic Centimeters) to the .30-06 capacity (4.4 cubic centimeters -- 3X bigger.)

In reality the .30 carbine is the "magnum" version of a .32 ACP (it's sort of like the difference between .22 and a .22 Magnum). When Winchester designed the .30 Calibre cartridge, the biggest change over it's 1905 .32 forebearer was the propellant, taking advantage of chemistry advances -- pushing more horsepower out of the barrel.

What's hard today is we have to put ourselves in a late 1930s mindset to understand the thinking of weapons developers then, not from our 21st century perspective. Our beloved M1 Carbines were designed as "Light Rifle" akin to a Pistol designed to get lots more horsepower out of a longer barrel.
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The Speer manual has some comparison data for 3 loads (light, medium, heavy) in 26 different revolvers. Each revolver got identically loaded cartridges and velocities were measured the same way for each. Examining nine revolvers with 6" barrels, there is a spread from a low of 1237 fps to a high 1603 fps for a 110 gr bullet. If they used an 18" barrel with a heavy load, they would have gotten the same ballistic performance as the .30 Carbine.
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BTW, I love my M1 Carbine -- it's a great rifle; I have nothing to criticize about it. Fantastic design. Superb performer. She weighs the same as my .22 carbines. But she was not intended to be a "Battlefield" nor "Assault" rifle.

The M1 Carbine is like a good wife -- you better love her for what she is, not what you wished she was.