Hello and welcome to the KCA forum. You are very fortunate to have inherited a wonderful family treasure like a Krag. Most of us have bought the Krags we have and don't have the personal family history like you have with yours. No matter what the value may be, your family historical value is priceless!

Briefly, the 1898 Krag carbines were made in a much lower serial number range than yours is. Authentic M1898 carbines were mostly in the 115,000-135,000 range. There are a few that are outside this range but not by too much. Dating exactly when a Krag rifle or carbine was made is a science unto itself. The barrel of a true carbine is exactly 22 inches measured from the front of the closed bolt to the end of the muzzle. We usually measure this by closing the bolt and dropping a cleaning rod down the barrel until it hits the front of the bolt and measuring the cleaning rod at the muzzle end.

You are correct that many rifle barrels, which are 30 inches, were cut down to resemble carbines. Krag rifles were very cheap in the 1920s and 1930s and people bought them and cut them down for hunting purposes. Bannerman and others were known to do this frequently.

Sometimes, a rifle barrel was removed and a carbine barrel was installed. This could preserve the front sight instead of replacing the front sight with an aftermarket sight.

Your rear sight looks like an authentic M1896 carbine sight which is marked with a "c" above the "19" (for 1900 yards) as well as on the right side of the sight which might be covered by the hand guard. We would need more pictures of the sight to confirm if it is real. These sights, by themselves, are worth north of $500. They are hard to find. If your rifle has been in the family for decades, it is probably authentic.

Please post more pictures of the front sight, rear sight, receiver with all markings and bolt. Can you see what condition the bore is in? Also, is there a set of cleaning rods in the butt of the stock?

Congrats again!