This is not at all accurate. No agent involved in the shoot out used a 10mm. The 10mm was developed because of the lack of penetration of the 9mm's that were used.
Originally Posted by pennys dad
The FBI evaluate ammunition with pistol based on it's penetration through an obstacle through clothes and depth of penetration into target. This method was developed because of the Miami shoot Out which ended in FBI Agents dying because the 10mm round penetrated car doors, person and car doors, it over penetrated. I have also seen the results of over penetration in my stupid teenage years.
I figure it this way, does over penetration happen, yes, does it always happen, no, should I plan for it to reduce its possibility of happening, yes. It seems like a good way to reduce accidental injury or death.