A few months back i watched a program on the History Channel about Heinrich Severloh, which was called Slaughter at Omaha Beach.
This man is apparently 'credited' with the most kills of any Wehrmacht soldier.
He fired around 12,000 rounds over a 9 hour period on to Omaha Beach and it is said that he killed around 2,500 men. After he ran out of ammo for his MG42 he used his rifle to continue firing at the oncoming enemy.
He only stopped firing and fled his post after his Liuetenant ordered him to do so.