how do i remove these drums?

so I picked up an A body 8 3/4 rear end the other day and it has 10 inch drums on it (I think)
they are the bell type drums

i backed off the adjusters to loosen the shoes up and when i put a screwdriver between the backing plate and the drum i can wiggle it but they refuse to come off
it almost seems like the drum is still attached at the very center of the axle

there is a cap in there (hard to explain, ill try to post pics tonight)
is there any chance this is threaded?

of do i just need a bigger hammer?