/summon command does not allow equiped mobs to spawn at specific coordinates

It's possible I am typing the command incorrectly, but if I wanted a Skeleton to spawn with a bow I'd type

/summon Skeleton

{Equipment:256}

But if I add specific coordinates

/summon Skeleton 10 10 10

{Equipment:256}

/summon Skeleton ~ ~ ~

{Equipment:256}

No weapon will appear in the mobs hand when summoned.