Crowd was lucky the shooter did not use Corbon rounds, which flatten and shatter forming a wall of powdered lead upon impact but continues to travel into the body causing severe trauma. It is said the round if impact in human chest, head and abdomen is a death sentence. Even if you survive, your insides are so shattered that you will die from internal bleeding. The only good news about the round is it will not go thru you and travel thru walls and etc, even at close range. Favorite for bodyguards, but in the wrong hands a mass casualty ordnance.
The fastest expanding bullets they sell like the glaser safety slugs use lead shot not powdered lead for the core with limits penetration but can cause some very large wound channels. But they are not a death sentence people have been shot with them and lived.
Shooting them through very heavy clothing or intermediate targets can cause them to under penetrate causing only surface wounds.
I haven't heard what bullets the shooter used but because we have not heard I am thinking he used FMJs.
Do we know what rounds he was using? I would guess FMJ round-nose “ball” since it came from WalMart. But haven’t heard anything official.