I am no Norwegian Krag expert here but, form what I have read and heard Krag type actions did take special care for heat treating simply due to their configuration. I assume due to the unique magazine? I have read that some observations are that if a Krag did fail it was often times in the front right corner of the ejection port. It is where the steel is narrower. Some Norwegian Krags had the steel squared out in this front right corner and some of the later Norwegian Krags and Steyr manufactured Norwegian Krags had a radiused corner there. The radiused corner was deemed to be stronger or better I guess from a design standpoint. Supposedly there was a lot of hand fitting done when Norwegian Krags were made but, I don't know for sure. I have put different bolt bodies in my Norwegian Krags and never had two fit exactly the same. That is just my very limited experience.
