There's differences beyond simply bullet diameter. For example, with .32 ACP, you're likely to use hardball. With .327, you're likely to use hollowpoints. With .380 ACP, it's about 50/50 whether people use hardball or hollowpoints. With 9mm, people tend to lean towards hollowpoint (but military skewed that towards hardball). With .357, you have virtually no excuse but to use a hollowpoint or similarly effective round over a hardball that will zip through.
They may both be 9mm, but if you're using hardball in a .380 to get the desired penetration and BJHP in .357 to get expansion, you are not going to have the same hole.
The .223 is only 0.003 wider than the .22 LR, but it is vastly more powerful.
