FYI, it's "38-55", not "38x55". The number-dash-number nomenclature is used for these black powder vintage cartridges. It typically meant a .38 caliber bullet backed by 55 grains of black powder. The same naming convention was used for a lot of late 19th century cartridges, such as the 45-70, 44-40, 50-90, 40-65, etc. Cartridge designations that are number-x-number are for more modern smokeless cartridges, and are usually metric. The numbers describe the bullet diameter and case length in millimeters, e.g., 5.56x45 and 7.61x51.
More importantly, you really shouldn't get load data on message boards like this. It's not safe. You never know where the data comes from, and whether the source is reliable and accurate. It's easy for guys to get confused and type in the wrong powder type or weight. You can then blow up a gun and possible hurt yourself. Always stick with published load data from reliable sources until you are very familiar with the cartridge and its performance, then critically evaluate anyone's suggested "pet load" based on your own experience with your gun and prior loads you've tried.
Hodgdon, Lee, Winchester, Lyman and many other publish load data for this cartridge. Just reference a good loading manual and you'll be fine.
