This is why handloading is so important . . . .for saving brass.
The Krag uses the thickness of the rim to off set the length of the chamber. Problem, there is not a component manufacturer that makes cases for reloaders that know what they are doing. Another problem, I do not know a reloader that knows how much clearance their Krag has because of the skinny rims.

I have checked/measured the thickness of the rim, most had at least .017" clearance. That must not mean anything to the component manufacturer because .017" is beyond field gage failure.

The purpose of the rim is to hold the case to the rear, excessive clearance, because of the thin rim defeats the purpose of the rim. And then we add the firing pin and primer,
and observe how DIFFERENT they appear. See how the shoulder has MOVED FORWARD a good amount?
The bullet, powder and case moved forward when fired. When fired the case locks to the chamber leaving the rear of the case unsupported against the bolt face.

And then comes the complicated part, when fired the rear of the case is driven back against the bolt face while the rest of the case is locked to the chamber. The case being driven to the rear of the chamber is the reason the Krag is subject to case head separation.

So when the case fills the chamber when fired leave it that way by not sizing the case or purchase cases that are longer between the datum at the shoulder and bolt face; but, again, component manufacturers do not make cases for reloaders that know what they are doing.

F. Guffey