The old Black Powder Report was a magazine about traditional Buckskinning and included stuff about original black powder cartridge guns. Was run by the Baird family as I recall. Heard somebody ran him into the ground suing over an unfavorable product review he did. He won the case, but went under paying the defense costs.
I think that part of it is that Black powder shooters have factioned off into trekkers, rendevouser's, Cowboy shooters and black powder cartridge fans. The ASSRA covers the muzzleloader target and schuetzen folks. Muzzle Blasts is about the only general interest muzzleloader mag left. The modern newstand muzzleloader hunting mags seem to be paid endorsements of various in-line products and super expensive bullets and non-powders. What might be really good, is if some one could get some of these publishers to cooperate with a bundle joint subscription deal. Pay one money and get three or four of the various mags.