How much did Goliath's spear weigh?

The weight of his spear wasn't given, the weight of the spear head was. That weight was 600 shekels, a shekel is .4 ounces. If my math is correct that means the head weighed 240 ounces, which is 15 pounds. A very big spear head! The shaft was the "size of a weaver's beam" which is about 2-3" around and about 6-8' long. A very big spear.

Considering Goliath was 9' 9" tall, he was big enough to handle it.