Idcurrie: The 256 brass you have is probably quite old. You should consider annealing the necks of the cases before you reload and fire them. That may forestall the brass from cracking along the necks.
Secondly, you mentioned the stock and steel butt plate being a concern to you. As the rifles have quite a bit of collector value you would be ill advised to replace the original steel butt plate with a recoil pad as it will diminish the value. A better solution would be to get a shooting vest with shoulder pad or an item similar to the Past magnum shoulder pad for use at the range. You won't notice the steel butt plate when you are shooting a couple of shots while hunting.
