DI, it won't hurt accuracy in any way as long as it is straight and level. Unknown why the base did not release after the JB Weld cured, perhaps there was not enough PAM on the barrel. There should never be any need for another scope rail (base) since these H&R rails are great. If you do need to take it off I would suggest heating the area well with a heat gun and getting it HOT or slowly getting it to temperature by fanning with a propane torch, do not get it anywhere near any temperature that would discolor or ruin the barrel or finish, after that with the barrel held securely in a large strong vise strike the rail sharply using a large hammer to strike a large drift or of some sort, perhaps and old large chisel with a dulled edge. Be prepared to replace the aluminum scope rail after any hits, you will not be able to save it. The BEST thing to do is leave it and know you have a solid base for you scope to sit on!!!!....<><.... :grin:
P.S. - I like Quicks method better, if you must (why?) try the freezer and block of (hard)wood as a drift first!!!