I took a look through the forum but could not find this topic anywhere and figured it would be faster to just ask than to do a really thorough forum search.

Both the Core rules and the GM screen say in the section on damaging hordes that if a Blast(X) weapon attack results in a hit, it does one extra hit. Should that really be X extra hit(s)? It seems logical to me that a Blast(5) weapon should be far more damaging to a horde than a Blast(1) weapon.

Am I wrong?

You are wrong. Look at the part titled blast weapons you will see that Blast(5) = 5 hits. I think you are looking at the explosive damage (X) as in X being the damage type meaning explosive doing one extra hit.

Thank you. You are right. That's exactly what I was doing. Thank you.

Your welcome! Since (X) is normally used as a variable its understandable.