I don't know what grain of bullet your looking for but I have used them before, and selected the Lyman #457125, .458", 500 gr., RN which is the 1881 500-gr US Gov design, good bullet for use in the Buffalo Classic's and Ultra model that I used to have. AS both of these rifles had a rifling twist of 1:20.
The real nice thing is that these bullets work great in my Remington Rolling Block 45-2.4"
The shipping charges are the same for 50 bullets or 1,000 bullets so I can live with that as well too.
Good luck and straight shootin.