I am looking for thoughts on shooting and loading 38/55 vs 40/65. I have been shooting 45/70 for a few years and would like to expand my shooting experiences with a new (to me) caliber. My shooting would be limited to 400 yards or less. I prefer to buy my cast boolits rather than casting them myself. I would make my cases if the process is not too difficult. Availability of production cases would help me decide. Any thoughts on brands of rifles that shoot those calipers is also wanted (single shot). Please give me some guidance.