You could try freezing the barrel in your chest freezer. Then after it is good and frozen(day or so) take it out and apply an immediate heat source. I do not mean a heat torch, just what ever you have that will heat it up fast. And apply constant pressure while it is heating. You might want to take the scope and stock off the rifle. Just be careful not to get it too hot. If that doesn't work then take it to a professional. Tom.