So the 10mm "light" was created, aka 40 S&W.
The 10mm "light" is the reduced load the FBI went with but still using the 10mm case. The .40 S&W was developed since a shorter case could duplicate 10mm "light" performance in a smaller handgun.
Almost all 10mm loads are "light" nowadays. Double Tap and Buffalo Bore loads are two exceptions. Comparing factory loads, it's not uncommon for .40 S&W to actually outperform the 10mm.
