How did it work exactly?
Does it Prevent or Reduce Crime?
Criminals rarely use assault weapons in violent crimes. They are large and so not easily concealed. They are heavy and therefore not conducive to carrying around all day. And, they aren't as nimble as a handgun for close quarters "work" like that required at a liquor store or other "stop and rob" convenience store. The choice of weapon for the criminal is the hand gun. It is easy to conceal, easy to carry, and plenty powerful and intimidating, regardless of its caliber. "Assault weapons" have been used for crimes like bank robberies, drive-by shootings and school shootings, but these are rare. The hand gun is by far the preferred weapon for criminals.
Does it Prevent or Reduce Accidents?
Limiting the features by instituting an assault weapon ban does nothing to prevent or reduce accidents. Firearms accidents are not the result of pistol grips, flash suppressors or folding stocks. They are the result of careless handling and use of firearms. Expecting a reduction in accidents based on prohibiting certain features on a weapon would only be possible if those features promoted unsafe handling or use of the weapon. Such is not the case with an assault weapon ban.