All U.S. army springfield rifles were chambered in 30-06 caliber.
30-06
With the serial number provided,your springfield model 1898 krag,was made in the year 1899.
1934-1935 They were on limited production.
probably 30/06 unless the barrel was changed.............
.30-40 krag
Model 1911a1
Your model 1898 krag was made by springfield armory in 1899.
Serial # N5102889 Made
30-06 but be forewarned that serial numbers below 800000 are dangerous to fire due to poor heat treatment. See: http://m1903.com/03rcvrfail/
Have to know what model of gun it is, than you could search by model and serial number. Try Fulton armory or doing an internet search.
about 1914
You would need to be more specific. You could be referring to the serial number, the caliber, a model number, armory/arsenal markings (in the case of surplus military arms), etc.