A friend turned one of his two identical Panda actioned LVs into a heavy. He added part of the weight by machining a brass weight that clamped on the scope rail, and filled all of the available space between his rings, up to the bottom of the scope. The rifle shot better after it was added. I think that there may be some advantage to distributing the weight rather than putting it all in one place.
Some years back, a friend bought a rifle out of an estate that weighed 12.5#. It tracked flawlessly, despite having a less than state of the art stock. He decided that since he was unsure of the round count that he would have it rebarreled and somewhat proudly told me that he was going to bring it up to the HV limit by putting on a longer barrel. I cautioned him that the weight was not a requirement, but an uppler limit, and given how well the rifle tracked, that I thought that he should give serious consideration to simply duplicating the old barrel's shape and length with the new one.
One time Dick Wright solicited questions on line for one of his Tony Boyer interview articles. My question made the cut. It was would he sacrifice barrel weight for rifle balance. The answer was yes.
