As I have been advised, a brake that needs to be indexed should not be removed very often. I have also been advised but never actually tested it myself that a barrel will shoot to a different point of impact with and without the brake.
I like the DE brake but it is indexed. A Vias type brake might suit your needs better for taking off and on a lot, but gas will come up into the field of view and downward blowing up dirt. Finally, a brake works off of the velocity and amount of gas coming down the barrel (and the perpendicular surface area impacted). The smaller the amount of powder being burned results in the smaller the effect of the brake reducing recoil. The 6mm will not get the same reduction as a larger case but then it does not need it.
Now the thing that your mother never told you is that even the most effective brakes do not eliminate the cloud of gas that travels straight out the barrel and momentarily obscures your vision. Even with the DE brake when the rilfe just barely moves and the brake affected gas is deflected sideways, it takes a part of a second for the gas that followed the bullet to clear. So when you go toad frog hunting and shoot an angry charging toad frog at 15 feet do not expect to spot your hit.
The Smokin Fur Rifle Club