regardless of what the FBI says or the internet says, a bullet traveling at 3000 fps will penetrate drywall and go thru. So will a 9mm and a 45 acp. Like i said, we did testing and there wasn't a clear winner here, all would have been deadly at 21 feet on targets behind the wall. We did see a 115 gr 9mm HP having weak penetration but still enough to cause damage behind the wall.