So I was wondering about this product, the Sims "Barrel De-resonator". I saw it in the Cabela's mag. and it caught my eye with the pics of the improvement in groups with this product. I'm sure there're other brands out there, it's a rubber looking donut that goes on the barrel and can improve your group accuracy. Also does this product have a better affect with sporter type barrels that have greater vibration? I have just never seen one on any long range rifles on this forum, so just had to ask.