Busting a nut trying to unscrew forend nut, help!

[superchief]

put your tube assembly in a vise with rubber jaws. get a GOOD forend nut tool. Since you should be contacting the assembly on the wood or plastic grip, give it some oomph and it should break loose. When it does, and you can't get the tube out, then your frustration starts. for wood grips, you can make a wedge and insert it from the back end of the grip to spread the wood out. for plastic, who knows?