David and Goliath misinformation

In the Efron text, the historians claim that a contradiction occurs within the verse of Samuel.  It says: A champion came out of the Philistine's camp, Goliath, and his height was six cubits and a span.  He had a helmut of bronze on his head, and was armed with a coat of mail; the wieght of the coat was five thousand bronze shekels.  He had greaves of bronze on his legs and a javelin of bronze slung between his shoulders.  The shaft of his spear was like a weaver's beam, and his spear's head weighted six hundred shekels of iron.  As the Philistine approached David, David ran quickly toward the battle line toward the Philistine.  David put his hand in his bag, took from there a stone, slung it, and struck the Philistine on his forehead.  The stone sank into his forehead, and he fell face down on the ground.  So David triumphed over the Philistine with a sling and a stone striking the Philistine and killing him.  (1 Samuel 17:4-7, 48-50).  Furthermore, the text places the "evidence" by explaining that David was probably credited with defeating Goliath as opposed to Elhanan.  In the next passage, it says: There was another battle with the Philistines at Gob; and Elhanan son of Jaaroregim, the Bethlehemite; struck Goliath the Gittite, the shaft of whose spear was like a weaver's beam. (2 Samuel 21:19).  Efron's claim is wrong because they missed another passage that disproves this argument.  According to the book of Chronicles, this is what the passage says: And there was again war with the Philistines; and Elhanan the son of Jair slew Lahmi the brother of Goliath the Gittite, the staff of whose spear was like a weaver's beam.  This passage explains that Elhanan did not fight Goliath, but fought his brother in another war against the Philistines.