You can use jacked bullets but it is best to use a slow burning power. Go to the web pages of the bullets you wish to buy and you can get the correct power loads. Start at the lowest and work your way up. Do not go over the top load. I am using IMR 4350,
Jim.

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Krag magazines work best when fed cartridges loaded to the same length as original 220-gr. RN military ammunition, 3.08". If cartridges are shorter, we just have to be careful to align the rims in echelon when loading.

For stability, it's normally best to seat bullets with at least one caliber (.30" in this case) inside the neck. Although seating depth has a significant influence on pressure (because it alters the powder space), this will not be a critical factor with the reduced loads dictated by your plain-base cast bullets. Seat to whatever length works best in the magazine and on target.

With commercial cast bullets, you get what you pay for.  Plinking, gong shooting at 100 yards, beer cans or the equivalent, the Acme sort will be fine.  Same for sighting-in.  If you are trying for MOA-type groups you may be disappointed.

With those light powder charges, best results will come if you use the Krag as intended, as a single shot, and elevate the cartridge bullet up to position the powder near the primer before loading.

As a test, you might think about tipping the cartridge upside down before loading into the chamber.  That ought to put the powder right behind the bullet.  Is that a safe test?

Safety glasses!!