This week, I have been getting 'intimate' with some Krags. (Checking head-space, recording bolt markings, noting wear, and measuring bolt-face to rear of lug dimensions, with FredC's fixture.

One exercise I performed, kind of amazes me:

I took two, 'once fired', cartridge cases and chambered them, without Re-sizing, in ten different Krags.
(I do not remember which two of these rifles or carbines, the cases were originally fired in).

All ten Krags were checked with a "Field Gauge", that has a rim thickness of .073".
None of the bolt/receiver matchups would close on this gauge, a couple of bolts came relatively close.

Eight of the actions treated these 'Fired' Cases the same as they would a Full Length Re-sized or new Factory Case. They showed no resistance to chambering the 'fired' case.
(FWIW - Six of these Krags have the Bolt, I obtained them with. Four of the Krags have Bolts that I installed for various reasons).

Two of the 'replaced bolt' Krags closed on the 'fired' Brass, but, with a bit of resistance. These Krags left bright rub marks on the case bodies, right behind the 'shoulder'.
One, of the two, showed 'sticky' extraction and required the bolt-handle to be 'slapped' upward with an open palm.

The 'sticky' Krag is one I assembled from assorted parts: a model 1898 receiver, in the 412K serial # range, mated to a pre-July, 1899, barrel. (I had to bevel the shank on the barrel, so it would fit the Receiver). Officially, the Chamber dimensions should be slightly different on this barrel. (See attached specifications).

This 'parts' Krag shows no difficulty with Brass that's been 'fired' in it.

The other Krag, that showed resistance to chambering the fired Brass, has a model 1899 carbine action, in the 349K serial # range, and a 22 and 1/8" cut-down barrel. There was no extraction difficulty.

I do find the "uniformity" of this sample of 10 Krag chambers remarkable.

(My experience with Lee-Enfield rifles, in .303 caliber, has been quite different)!

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One more experiment to try is fire a couple in the ones the Field gauge almost closes on, then try those cases in the others. This is also a testament to how much the brass springs back after firing at moderate pressures.

Had two sporters and there was enough difference in chambers that brass from one would not come close to chambering in the other.  Fortunately had both R-P and Win brass so dedicated each make to one to keep it simple.