Originally Posted by Fishinfool

Chosin - Some unburned powder / debris is common with 296 powder. As others have said, a magnum primer, good crimp, and good case tension on the bullet will all contribute to complete burn and consistency with this powder / bullet combo.

Do not keep increasing your powder charge looking for pressure signs or a cleaner burn. It's not safe. You are already about there... I have loaded quite a few 300 grain jacketed 44 mags with 296 over the years, and you are right where you want to be between 20 and 21 grains of powder with a jacketed bullet. You are probably looking at about 1150 to 1200 fps velocity at 21 grains of 296.

You can get a little faster velocities with a cast lead 300 grain bullet, and maybe a half grain more powder.

A 300 grain bullet at 1150 / 1200 fps out of a handgun is a powerful load. If you want appreciably more, a step up to something like a 460 S&W is the way to go.

By the way, lack of muzzle flash with 296 is a good sign of pretty complete burn. If you want flash, try a 180 grain bullet with a book max load of 296 in a 4 inch gun...

Larry