"Assault pistols" with 2 or more banned features are not permitted in Hawaii. This doesn't apply to shotguns or riffles with a 16inch or greater barrel length.
Some states have restrictions, banns, or require owners to register firearms they conceder to be "assault weapons". The definitions of an "assault weapon" varies widely from state to state. These definitions can include whether the gun is fully automatic, the magazine size it can carry, and others.