Thats a hard one to say. On the one hand, if its just rusty (which was my issue) then you probably won't hurt anything using a good deal of force. Mine was stiff the whole way out, even once it get free'd up there was enough rust build up that there was a lot of friction still.
On the other, if it is cross-threaded, you might hurt something. That said, if its cross threaded, what else are you going to do? Just leave it? Its not like you can really tell if its cross threaded or not without removing it?
It went in finger tight, and I only snugged it at the range with the tool to make sure it was not loose. It is definitely not rusted. I could have maybe loosened and the force of the shot cause it to skip a thread? I might try with the vice a little bit, but I'll pick up some better penetrating oil and let it sit at least overnight first.
BTW: Is transmission oil considered a good penetrating oil? I've seen it used for cleaning before, but not sure.


















































