[Westbrook]

From 1st Samuel 17 ...

50. So David prevailed over the Philistine with a sling and with a stone, and smote the Philistine, and slew him; but there was no sword in the hand of David.

51. Therefore David ran, and stood upon the Philistine, and took his sword, and drew it out of the sheath thereof, and slew him, and cut off his head therewith. And when the Philistines saw their champion was dead, they fled.

OK. You could read it either way: that Goliath was dead when he hit the ground, or that he died when David removed his head. Given the nature of oriental narrative, I submit that you are correct in assuming the latter is more likely.

[American Constitutionalist]

These biased liberals who write these articles want to revise history in a way that future generations won't really know the truth and what happen.
Given that David was a real shepherd and protected sheep he must have plenty of years to practice his slingshot abilities on bears and lions and it does not take a stretch of imagination that his aiming with that slingshot was very accurate and knocked the ungodly heathen liberal Goliath out cold.

[MrB]

The severed head would seal the deal regardless.
I like the idea, though, that the Philistine died by his own sword.