I've used the Remington and Speer bullets, but these days I mostly use my own cast bullets. A big ole 405 grain slug, poking along at about 1600 fps, jacketed or cast, is nothing that game animals care to stand in the way of. Somewhere out there are idiots who think that you can't shoot a cast bullet out of a microgroove Marlin. Somewhere out there are a whole bunch of Marlin owners who know otherwise. Try some carefully loaded cast bullets sometime.