'gtbee80' - It does appear the front face of your Krag's receiver had a bit of metal removed.

That is probably not a problem in itself, because, that is not what controls the depth to which a Krag  barrel screws in.

Your receiver ring measurement of 27/32 inches = .84375"

FWIW - I measured the length of three different model 1898 Krag receiver rings with a vernier caliper. They ran .880", .881", and .885".

I estimate about 37/1,000" or a little over 1/32" of metal was taken off the front edge of your receiver.

The Real Problem???

My hunch is that someone removed 3/4" of the rear portion of your barrel and then failed to chamber it deeply enough for the .30-40 cartridge.

I believe a regular Krag barrel would still work on your action, because, the breech of the barrel actually stops and seats on an internal shoulder (and not the front edge of the receiver).