teflon tape and rega RB300 arm

If you don't mind taking the arm apart, use 3:1 heat shrinking tube around the arm tube and heat it up to fit snuggly.

I use the Teflon tape tweak on my Linn Basic arm and the result is very beneficial; a noticeable reduction of resonance. BUT, the Linn is a low mass arm and I don't think the rb300 is, so results may vary.

The only drawback for me is the tonearm now is kind of ugly, but makes for a good topic of conversation.

Why not use premium grade vinyl electrical tape? I have also heard about people using liquid paper to damp tone arms.

I could have used pure silicon tape, or 3m 33 electrical tape but did not want to add extra weight, the teflon is much lower in weight than other tapes.