There is a rather unscientific condemnation of it on www.bellmtcs.com . Other than that I don't know. Does anybody remember seeing a small black ring near the end of the barrel on the Monster Bucks videos on some of the rifles about 5 or 6 years ago? I wonder if this was something similar?
The critters have to win every time, I only have to win once.
I have used one on a Sako rifle that I built years ago with a Douglas barrel in .223.It seemed to tighten the groups but I haven't done any extensive testing as to find the right sweet spot.The device is somewhat hard to move on the barrel without some sort of lubrication.Good luck if you try to use one.
Hopefully we can get Bart B. to comment. I've read some of Barts comments on other snake oil panaceas that lead me to believe it's bogus. Are the high power winners clamoring for it? Is there any evidence it works?
some shooters in differant circles have been trying differant things to get their guns to shoot better with a given load.
Say your shooting a 168gr SMK out of a 308 and trying to get to 1000yds , the bullets are making it but they are falling into subsonic range before they get their and accuracy is suffering, you have a load that is faster and will keep the bullet supersonic out past 1000yds but its not the most accurate out of your gun so you can "try" to tune the gun to the load. either by cutting down the barrel very little bits at a time trying to find the harmonic sweet spot or you can use some sort of weight ie the barrel de-resonator.( this was strictly an example)
I've heard of rimfire shooters using wads of rubberbands wrapped around their barrel and sliding them up and down to try to find a sweet spot..
Do they work , I'm sure that in some cases they have been proven to have an advantage. are they ugly? YES is their a better way to get accuracy? YES
even if I coulden't get a gun to shoot well by accurizing it and tayloring a load I don't think that I would waste my money for a chunk of rubber to try to fix a problem that needs actual work done to it.
On another note , the Sims products for archery gear work great I have never seena bow that they diden't help so the company doesen't seel all bunk stuff they just ran accross an Idea that they thought would work well and I sure they have made alot of money off of it.