I recently picked up a 336 Marlin in .35 Remington for Cowboy Silhouettes, given the success people have reported with heavy slugs in .357 Magnum revolvers I estimate a 200gr cast at 1500-1600fps should be plenty for all animals. I've seen people favoring Unique and 800X to get cast bullets to that speed range, wondering if anybody's tried American Select for such a purpose.