[Drefizzle]

I just heard about something called a barrel donut, I guess they are for vibration and recoil damping?
All I could find on google was patent info.
Are these thing real?
Do they work?

 

[Ram Rod]

Talking about a barrel tuner? Those things are real.
http://www.webspawner.com/users/bugholetuners/
http://www.benchrestspecialties.com/barrel_tuners.htm
http://www.varmintal.com/a22lr.htm