We can answer questions, but there have been books written on the Krag, so it would be difficult to cover all the details on a web site. Generally, there were three models of rifles, the Models 1892, 1896 and 1898, and three models of carbines, the Models 1896, 1898 and 1899. The Model 1892 carbine was experimental only and never issued.
Carbines are scarcer than rifles and bring more money so many are fakes, made up from cut-down rifles. Some rifles were cut down by the Army to carbine length for special purposes and also for sale to NRA members through the DCM.