Check out the "GBO Reamers" sticky in the NEF/Handi forum. If you want to give the reaming a try Tim (Quickdtoo) has all the instructions for you there. It's quite easy to do really. A good solid vise and some cutting oil is the most of what you need. Pays to be a little gentle/careful the first time, again, Tim has really good suggestions he includes when he ships the reamer to help out. The worst that might happen is the chamber might need a little light polishing right at the transition point between the original chamber and the new. I think a lot of the time the factories push the reaming pretty hard and the chamber tends to be a tad os right at that point.
Ron