The bullet is steel jacketed. Will that put up too much resistance to be tapped out? Thank you.
Steel? Forget pounding it out, you need to press it out. After you get the barrel secured you need to rig a hydraulic jack that you can pump up slowly pushing the rod against the bullet and ease it out of the barrel. A light squirt of lube in the muzzle will probably help, I doubt the penetrating oil from the breech will do you much good. If you can't figure out a way to secure the barrel and rig the jack then take it to a shop and have them do it for you, gunsmith, machine shop, auto body shop, maybe a machinist friend if you know one.
I can't figure out why I always hated steel jacket bullets...wait, wait, its coming to me.