I don't know how you could possibly "eliminate" or "dampen" barrel harmonics. Maybe it's me, but I think those are a poor choice of words. From everything that I've read, plus my personal experience with bedding and floating forends, I would say it's bedding a stock and floating a forend in order to obtain "consistent repeatable" harmonics from a barrel. Then you can develop your reload to find out which one (or ones) work the best with that barrel harmonic.

MHO

Dave