If Hitler had access to modern weaponry during the Holocaust: - The Holocaust could have been longer and resulted in far more deaths than the estimated 6 million Jews killed, as modern weapons are deadlier than those used in WWII. Gas chambers may not have been needed as much. - Large groups of Jews could have been killed instantly on the spot with modern rifles, machine guns, and other weapons. - Hitler may have succeeded in exterminating all Jews, and moved on to target other races for destruction with the powerful modern arsenal at his disposal. His descendants may have continued his genocidal goals unopposed.