Detail of barrel...of there were ever properly spaced holes drilled they would be ~0.75" to the left of each of these holes.

'gtbee80' - Welcome to the KCA Forum.

Your "carbine", #105621, is actually a U.S. Model 1896 Krag-Jorgensen rifle that has been shortened. It is easy to misread 1896 as 1898.

It is possible your Krag's barrel is a replacement and not an original Krag barrel. Or, it has been shortened 3/4" at the breech, re-threaded and re-chambered.

Either possibility might explain the incorrect sight hole placement.

Your barrel's taper does not appear to fit normally in the Stock's barrel-channel.

FWIW - Attached photos show correct Krag barrel breech and extractor-notch, Krag barrel proof "P", and index mark on action/barrel.

Compare your stripped Krag with my photos.

The lower pic's front sight mounting doesn't appear to be original.  Hard to tell what the barrel was made from, it doesn't quite appear to be Krag taper either.  You could get a blank repro handguard and cut your own sight slot, or mount a receiver sight and leave the blank handguard covering your holes.  Since you have that tall front blade, you might be able to get it on target.

Thanks all and I think you're on to it. Attached are (not the best) pix.

1. The chamber area looks OK or the same as BR, please comment if I'm wrong or missing something.
2. I see no 'P' proof mark anywhere on the barrel...plus...I see lots of 'scars' on the barrel near the chamber as though in a vise or some sort of toothed grip...artifacts of the re-barreling (??).
3. The muzzle crown looks like another '98 Krag I have that was cut to 24.5" while my other two unaltered '96's have a more smooth & rounded muzzle crown that to my untrained eye looks genuine.
4. Agreed on the front sights observations.

Appreciate all the help!

OK, thanks BR!

I took a quick look at the chamber of another one of my Krag"carbines" and a Krag rifle and the former had a similar but less pronounced artifact/annular ring/thing and the latter did not (matched your original picture). So that makes 2 of my pieces with this artifact/annular ring/thing.

I will tear the 2nd one down & post pix, may take me a day or so.

Sorry for the delay responding, had a death in the family but it was expected.

More on 105621, I don’t know the history, it was bought at a gun show (truly a “show special”, appropriately priced in hindsight) at the end of 2016 and am just now getting to it, but it does not chamber a round (bolt won’t close on a round) but bolt closes OK without a round. See pix, this round is pushed in by hand, looks like 1/32 is exposed past rim (tried several rounds, none fit in 105621 & all chamber smartly in other Krags). I swapped bolts around for completeness, same results. The rim of the round is well clear of all metal so the issue is in the chamber. At this point I’m taking BRangers suggestion of a cut-down & re-chambered barrel as gospel (originally a 30” and cut at both ends to result in 22”). The original index mark on the barrel is missing but what looks like an extension of the mark is scribed into the barrel (for use later after the original chamber was cut off & original index mark gone). So guessing this barrel needs to go, suppose best replacement option is CMP/Criterion but as always suggestions/guidance is appreciated. There are no blockages in the chamber, chamber walls are smooth & polished & “look OK”, whatever was done seems intentional yet the results are the results. Wondered if it was chambered for a different round but can’t think of one that is only slightly smaller than 30-40.

As for the receiver…there is no ‘P’ mark on the face of the receiver and the index mark on the face of the receiver is not there (but there is one on the side…see pix). If all that is supposed to be on the receiver face then I suppose some metal has been removed from the face as part of this hack to get everything to index marks to line up. Looks like the barrel should is 27/32” (see pix)…WHAT SHOULD THIS BE & IS IT “OK”? Also reflecting on MShooter’s comments of ‘feed ramp work’. Rounds do feed & eject OK, with & without magazine cut-off …so is this receiver still "OK"?

I discovered that the face of the receiver on US krags isn't square when I rebarrelled one with a larger diameter barrel that had a flange.  Receiver should still be ok, looks like most material came off the edge of the barrel.  I'd rent a 30-40 reamer and make use of it before rebarreling, if it has good rifling.  It's weird that a 30-40 doesn't fit, why modify the edge of the barrel if what you're trying to feed doesn't fit the chamber?  Maybe you have something in the chamber, a bit of old caseneck or something like that.