Legislators and members of the press have proposed placing increased restrictions on all semi-auto firearms, which would include some hunting rifles. With muzzle velocities that are often greater than standard long guns and high-capacity ammunition magazines, assault weapons are built to kill large numbers of human beings quickly and efficiently. In tests at their firing range, San Jose, California police found that a fully automatic UZI could fire its 30-round magazine in slightly less than two seconds. Most assault weapons have no legitimate hunting or sporting use. Assault rifles and shotguns often have pistol grips and folding stocks and are typically lighter and more concealable than standard long guns.
Some assault pistols have threaded barrels for the easy attachment of silencers.
Many assault weapons are merely semi-automatic versions of military machine guns, making them easier to convert to fully automatic machine guns. No exact figures are available. An unknown number of these weapons have been illegally converted to full-auto.