Firearms News (formerly Shotgun News), February 2018, Issue 4, Sarco advertisement, page 96, bottom right hand corner:
"Would you believe.... original G.I. U.S. Krag Receivers! original 1898 Krag receiver from old, old, old government auction. Very good condition. Spring Sale!..... $29.95 3/$79.95 10/239.95." The ad doesn't say, but these might have to pass through the books of an FFL-- but still a pretty inexpensive start.
Personally, if I wasn't already in possession of 4 complete actions, I'd already be making the phone call. (Sarco 610-250-3962,
www.e-sarcoinc.com)
I posted this because I've seen several posts in the past by those wishing to build or own a Krag. Here's where you need to start with-- a receiver. These nice old rifles are rapidly vanishing into the dust bin of history, and finding one in as-issued original condition is becoming both pricy and difficult. There are many "sporterized" specimens floating about, all whacked, chopped, and customized to varying degrees, some better than others, most with a lot of wear and tear. However, I do believe that if you're in the mood for a "project" and have the time to continuously and repeatedly peruse e-bay and the offerings of the parts companies you can still assemble a very nice rifle from parts. Were I going to undertake the project I'd likely use a new reproduction stock and appropriate hand guards (nothing as nice as new walnut!), but even the stocks can be obtained with enough searching.
Good luck with your project! You can PM me for any problems/questions you might encounter if you decide to "go for it".
DG