I've got a JL lefty pipe on the Stella. Looks like this It's got a bunch of rivets on the expansion chamber side of the silencer; 3 rivets on the tip end. Conventional wisdom says you'd drill out the 3 on the tip end, pull out the core. Drilling part completed. Yankage commenced. It's not budging. Do I simply apply more gorilla force to it or am I missing something?