Thanks Hawg. Saw both his videos and the one from Midway. They just turn the tube and push the slide forward and the thing comes off. Mine doesn't. It may be that the threads are really dirty and I need to keep soaking it in CLP and working it. Am at a loss for anything more than that...
It does not appear to be on backwards - the tube turns the correct way to unscrew and seems to loosen and stop but the thing just won't let go.