I HAVE THE SBE2 WITH THE SMOOTH BORE. I JUST PURCHASED THE FULLY RIFLED BARREL (12ga) AND NOW FOUND OUT THAT I MUST PURCHASE A NEW FOREARM FOR THIS BARREL,, TRUE?? SOMEONE SAID I CAN MODIFY THE ORIGINAL FOREARM AND STILL USE IT FOR BOTH BARRELS? ALSO, THE SLUG BARREL IS FROM A SBE. ANY THING I SHOULD KNOW WHEN INSTALLING IT TO THE SBE2?? THGANKS