PREDATE
Not trying to start another war... but there are such better projectiles out there that will offer a higher percentage terminal perfomance than a Power Belt. Remember a Power Belt is nothing more than an elongated Round Ball, cunsrtucted of a very soft lead. If you are going to use a Power Belt or a lead conical I would suggest you use a heavy one.
So I think you have the right idea looking in another direction. It is my understanding that Power Belts or even Round Balls will work best with light to moderate charges. Over powering them can lead to the bullet destroying itself on impact. Shooting them at the recommended velocity they seem to perform well but the drop in the extended ranges is drastic... Still with enough practice you can compensate for that.
With any luck... If the Big Brown shows up early enough today - I am going to test a new sabotless bullet in an Omega - it will be intersting to see how it does. I do not even know what weight it is yet.