I have used quite a bit of it in testing. I have weighed, and compared it to Winchester brass and it seems to be just slightly heavier. So far, I have not had any of the primer pockets loosen up, but I don't have more than just a few loadings through any one case.
I am working on three wildcats all based on the WSSM case and will be using the Federal brass for those. The neck seems to be a little easier to work with.