You will have to buy a 357 mag and have it reamed to a Herrett. I will probably do this in the next year or so, because I had a Herrett in an original contender and liked it, and 30/30 brass is copious while 357 Max is not. If a trapper 357 barrel comes up for sale I would love to get my hands on that, just for that reason. Meanwhile, I am looking for a 357 ejector barrel which I will send to trotterlg to have reamed and maybe cut to 16.5". That, with a synthetic youth stock set will make the ultimate "shorty" as far as I am concerned.