The hub center is what keeps the drum concentric with the axle- - - -the drum is a tight slip fit over that part. Try smacking the flat part of the drum between the lug bolts HARD with a steel hammer, not a soft mallet. Just aim well so you don't damage the lug bolt threads. The shock of the hammer sandwiching the drum center plate between it and the axle flange will usually jar the rust loose. Be sure the brake shoe adjustment is backed off as far as possible. If you do have self adjusting brakes, it will be necessary to use a small punch or screwdriver to release the self-adjuster before trying to back the adjuster star wheel up. Drum pullers just bend and distort the drum center- - - -use one only as a last resort and be prepared to discard the drum. Good luck!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!