The pussies at the FBI get the thanks for that!
No they don't. You're parroting a myth.
The FBI only ever issued their 10mm with a downloaded round, a 180-gr Sierra bullet at 950 fps (vice Col Cooper's 200-grain bullet at 1,200 fps), often called the "FBI 10mm Lite" load. Before they ever issued that first S&W 1076 to their agents the FBI did extensive ballistic testing on the cartridge and determined their goals could be met with the FBI Lite load, which also would be cheaper to manufacture and put less wear-and-tear on the firearms.
The FBI NEVER ISSUED a full-house 10mm Auto round, only the FBI 10mm Lite.
The FBI Lite load left so much unused case capacity that S&W sensed the business opportunity and approached the FBI with the idea of a 10mm cartridge shortened by 0.142" (allowing for a substantially less girthy grip) but loaded with THE EXACT SAME PROJECTILE AND TO THE EXACT SAME MUZZLE VELOCITY as the FBI 10mm Lite. And they called it the .40 S&W.
Which means the FBI's issue .40 S&W load was ballistically identical to their issue 10mm Auto load. Which further means it killed just as dead.
The story that the FBI ditched the 10mm because their agents weren't manly enough to shoot it is a complete fabrication still being perpetuated 30+ years later by people who would rather sling baseless insults at the FBI look into the facts of the story.