Thomassen: Your picture does not show detail clearly. A close-up, using natural light on an overcast day, will give much better detail. If your bolt is cracked and your bore is rough, you are probably going to be better off saving and searching for a replacement Norwegian Krag and scraping this one for 'parts'. IMHO (I played with your picture a bit and it looks pretty suspicious)!
I can't see anything in your picture. Too dark. Try taking them again. Bolts show up on GB from time to time but you need to make sure it is fitted properly. (gun smith who knows Nor. Krags) The primary locking lug should never be the rear bolt handle on these. If this is a sporter, and if the bore is not great I would look around fo another one. Get some reloading manuals like Lymans and Hornadys and use their recomended loads. I found that Hornady started out just a little too low for my N160 powder and certain bullets.
I tried taking a better picture outside, but I still get a lot of reflected glare even on an overcast day. I can pick up a replacement bolt body for $82. I wouldn't want to spend more than that trying to bring this baby back. Keeping it as a parts gun and saving for another may be what I do. :-[ On another note, I ve thoroughly enjoyed being on this forum. Thanks for all the great feedback. Hope you all are having a Happy Thanksgiving. :)
I decided to take a better look at the suspected area. I removed the blue and took a closer look under a Hamilton Bell 10x jewelers loupe that I had laying around. It appears to be a semicircular pitted line and not a crack. I've gone ahead and ordered a bolt from Numrich, anyway. No gunsmiths around where I live. I'll eventually locate one and have it checked out more thoroughly.
I was looking at one of my US Krag bolts and noticed that one of the machining operations used to form the locking lug where it joins the cylindrical bolt body contour left a faint arc-shaped impression or discontinuity in the surface. I'll try to take a good picture. I hope that's what you have on your bolt.
I've heard of people using rubbing alcohol, mineral spirits, or even gasoline (carefully) to determine if they have a crack. The idea is that you soak the suspected area with the liquid, wipe it off quickly, then look for more liquid weeping out of the crack. If there's no crack then you won't see additional liquid coming out. Maybe anyone who has tried it can let us know if it worked.
Nice detective work, gunboat. When I think of a crack I think of something that shows a clean break. My fingernail arc appears more like etching or slight pitting. I noticed it travels down the side of the bolt longitudinally. Hard to see with the bluing.
Hmmm. I love a good mystery. If your discontinuity travels for some distance longitudinally down the bolt toward the rear, I'd be more inclined to think it's just the mark left by a radiused milling cutter that lifted off just forward of your ejector groove. On my US Krag bolt there is more than one place where a change in cutter type left arc shaped marks. Makes sense because the Krag bolt could not have been turned on a lathe (except for the front end and internals), but must've been milled or cut with a planer or shaper. I wish I could find pictures showing how Krag bolts were machined.
I had one US Krag with a receiver that was cracked. The crack radiated outward from the locking lug recess, pretty much a mirror image of the cracked bolts shown above. Serial # was around 13000 and it was very hard and brittle.