Sen. Dianne Feinstein (D-CA) claims the 1994 Âassault weapons ban lowered crime even though a Department of Justice report shows it had no impact on recorded figures. Sen Dianne Feinstein â @SenFeinstein While the federal assault weapons ban was in effect (1994-2004), the number of gun massacres fell by 37% and the number of gun massacre deaths fell by 43% compared to the previous decade.