Ed, others have advised not to push the old Krag too hard & they are right.  Your load of 44.3 grains of 4320 seems more than a bit too much for me and I would not use that load in a Krag.  I messed about with 4350 and 4831 and 220 grain bullets and wound up cracking a bolt lug.

Most of the older writers, from Ned Roberts to Phil Sharpe to Ken Waters made recommendations on handloading the Krag.  All made reference to maximum loads in some manuals being entirely too hot for Krags. 

The Powley computer gives optimum performance for the cartridge, not for the rifle.  There have been stronger rifles than the Krag chambered for the Krag cartridge.  In the old days, the Remington No. 3 Hepburn and the No. 5 Rolling Block, the Winchester Single Shot and the Winchester 1895 were made for the Krag cartridge.  More recently, the Ruger No. 1 and the Uberti "Winchester" High Wall and maybe others have been chambered for the Krag cartridge. All are stronger than the Krag rifle. 

Get or borrow several different manuals.  Older manuals may have more data on loads for the Krag rifle than newer manuals. Read them carefully, especially where they tell you what sort of test rifle was used.  Then note what starting loads are most often recommended.  Also, you might consider 4895 or 4064 or 3031 powders. 

What are you going to shoot?  Targets?  Just plinking at a few bottles or cans?  Deer hunting?  Going to take a crack at a moose?  Pick a load suited to your intended use.  4831 (and maybe 4350) sometimes work best with magnum primers for optimum ignition, but unless you are after moose, how necessary is that?  Do you really need 2200 or 2400 fps to poke a hole in a paper target?