I have them in two of my 52d's. I've experimented with them. They don't work or help accuracy whatsoever. Best thing to do is get a Hoehn tuner with all the heavy weights if your going to shoot the factory barrell. Ron Hoehn will fix you up and your rifle will shoot better if you can find some good ammo.
Find the good ammo with the tuner off, and then install the tuner.
A tuner won't make a bad barrel good, bit it will make a good barrel better.
Good luck, Dale McClure