Right now, I'm in the process of evaluating one of the Limbsaver Barrel De-resonators. I tried it last week on my Ruger 77 in 300 Win Mag. I didn't really notice any difference in accuracy with it on or off. All the groups were with the same ammo and were all around 1 1/4". I am thinking that the barrel on the Ruger is pretty heavy. I'm going to try it on my Browning Micro Hunter 7mm-08 this week.
I'll let you guys know if its worth the $15.
pdougherty, if your rifle is older and has quite a few rounds through it, you may want to buy some JB Compound and run it through the bore in accordance with the manufacturers directions. Even with good cleaning practices, you can get some fouling buildup in the rifling over the years which can deteriorate accuracy.