When I first started reloading for the .357 Magnum in the mid-seventies, I loaded some with Hercules 2400 powder. Despite using magnum primers I still had some unburned powder granules with 4 inch barrel revolvers. There was bright flash and loud muzzle blast. When shooting with a six inch barrel revolver, the flash was still there, but was not as pronounced. Additionally, there was more complete burning of powder with less unburned powder granules.

I got away from Hercules 2400 and Hodgson's 4227 because of this. I hope that 2400 works for you but keep in mind that there ain't no such thing as a free lunch.

HTH.

JPJ