See how it says Lock level 450?
Volatile Seaforium Blastpack
Against Cataclysms version that says 525.
I have not personally made or tested the Powder keg. This is at the very least a terrible typo and needs to be fixed or is at worst a horrible oversight and again needs to be fixed. It is currently better to farm old world content and use Volatile Seaforium Blastpack than it is to waste mats on Locksmith's Powderkeg if the text is to be believed.