I'm not sure anyone will ever know. He clearly was a skilled sniper and the counter sniper engagement is reported in Zaitsev's memoirs although it is not certain that Erwin König existed. The 250+ claimed kills for Zaitsev seems certainly to have been inflated - although he himself acknowledged the total. His exploits clearly provideda morale boost at a critical period. Unqustionably he was very, very good so my "work of fiction" is harsh. He was there, he was a very good sniper. As for the totals, the existence of Konig etc..... who knows?
Red