The answer to this question can be somewhat confusing under California law. Take for example, a situation where someone points a gun at someone else. While it would seem like this would be an obvious violation of California's “assault with a firearm” law, it isn't. And before we could say whether this qualifies as the California crime of assault with a deadly weapon (ADW) or an assault with a firearm, some other questions would have to be answered first.
Was the gun loaded? If not, these circumstances don't violate California's “assault with a firearm law” because there is no actual ability to shoot someone. But instead let's say that rather than pointing the unloaded gun at another person, the individual used the gun to “pistol whip” the victim. Under these circumstances, the offense could be either an assault with a firearm or an ADW.
And how the offense is classified is actually very important as well…especially if the firearm is a machine gun, assault weapon, or semiautomatic firearm. An assault with one of these firearms subjects an offender to three to twelve years in the state prison. An assault with a “generic” firearm subjects an offender to six months in a county jail to four years in prison. An ADW doesn't even carry a mandatory jail or prison sentence.
So while it may not seem like there's a significant difference between the phrases “assault with a deadly weapon” and “assault with a firearm”, they have very different legal definitions and very different penalties under California's gun laws. (On a related subject, see our articles "The consequences of staged accidents under California law" and "The connection between ADW, brandishing, and criminal threats in California.")