Yikes! No release and bedded full length including the barrel. That's unforgivable.
I've never done this, but possibly the least risky approach is to freeze it at least overnight (in ND you could just leave it on the back porch
in the winter - maybe get it "really" cold), the colder the better - then use some sort of an action pulling tool, probably home made with a jacking screw, to put pressure on the action and a plastic dead blow hammer on the barrel end. The combination of the pull and the shock may work.
You might be able to pack it in dry ice in a cobbled up foam cooler for 4 or 5 hours to get it well and truly frozen if we are too far into spring to do it on the back porch.
If it freezing doesn't work, I'd try heat, but frankly the metal meeds to be heated to 250F to 300F, or maybe even 350F to significantly weaken the epoxy and that may be hard to do with out damaging something. .