IMO the Krag is one the most beautiful service rifles ever made. They are works of art. They are not the strongest action around, but will handle factory ammo or sane reloads just fine. Might have a smith check it before if you plan to shoot it.
They are getting pricey, for sure, especially the Carbine Models. If it hasn't been cut up best to leave it be. Worth much more in original condition. If it's been drilled or cut then you can do what you please. Damage is done.
Ammo is still out there and it's easy to reload the 30-40 as it uses standard .308" bullets available everywhere.
After searching for years I found this one in 1991 at a show and bagged it for $80. The stock was heavily and badly "customized" so I bought a semi-inletted (emphasis on the semi as it required MUCH more fitting than I anticipated) stock and replaced the ugly front sight with a Williams ramp.
I like it.
