Lots of good powders/loads for target velocity, cast bullet 38/55. Around 20 gr. of Rl 7 is as good as any. Check a manual for loads with 4198 (H or IMR) or 4227. I've used all these with success. I just don't have loads for the last two powders safely enough in memory. This is a great handloader's cast bullet cartridge. Enjoy.