Norwegian Sporter Krag

[Thomassen]

The bolt I ordered from Numrich came the other day. I cleaned it up today. Just for fun I measured the bolt with my dial calipers from the bolt face to across the hole for the cocking piece/firing pin rod assembly. I then compared the length to the original bolt. Both measured 5.669 inches. I'm thinking that if head space was fine with the original bolt that its fine with the replacement as they are the same length. Any thought?

Concerning the original bolt, a friend of mine who's an engineer and works making parts for the aerospace industry offered to take it in and check it for cracks.. The saga continues. I'll keep you all posted.

[gunboat57]

A more functional measurement would be from the bolt face to the rear of the front locking lug. That's the dimension that holds the cartridge in the chamber, so to speak. This assumes that your original bolt wasn't really cracked.

Looking forward to hearing what your friend finds out!

[Thomassen]

Will check it out.

[Thomassen]

My friend was able to take the bolt to work a couple of days ago. I removed the bluing (wasn't original) for easier readings. They used a liquid penetrant process and I am happy to say that there are no cracks whatsoever. I am definitely a happy camper.

I've also been able to find out a little about this rifle's history. It was issued to Artillery Regiment #3 from 1913-1940. AR 3 was stationed in the Southern part of Norway around Trondheim. AR 3 was able to occupy and hold the old Hegra fortress outside of Trondheim from April 15 until May 5th after the German invasion. AR 3 was the last organized unit to surrender in what is considered Souther Norway.

My 19 year old daughter put things in perspective for me as I fretted about the bore condition and possible crack near the bolt face. "It's still a cool rifle, dad", she said, "Even if it does't shoot great. There aren't many of these around and it has an interesting history".

She's right. And it is is the only rifle in my collection of 9 C and R military rifles whose history I can trace. :)

[gunboat57]

Congratulations! Now it's time to find out just what that rifle needs to be fed for best accuracy.

I think your daughter has a wonderful perspective. She reminds me of my own daughter who gave me similar encouragement from time to time. That's one reason why all my gun safes are overflowing!

[Thomassen]

I think I have a wall hanger here. I took the Krag out today and camped out at the 20 yard line.
Load:
140 grain Sierra SBT
Remington Brass
Winchester LR Primers
35 grains Varget

2 to 4 inch groups. Pretty erratic. And this was at 20 yards.
Primers still backed out. I had five blown primers (felt the gas on my face).I took a pic of 4 of them. Some pitting on the bolt face.
I dissected one of the blown primer cases.
There was no evidence of thinning of the case head.

I'm wondering if the primers are slightly undersized. Here are my pics:

[FredC]

I can not help but think you have 2 issues going on. Head space issues maybe indicated by the primer backing out. Your trouble with the sealing may be an oversize chamber. I just checked the SAAMI dimensions for both the chamber and cartridge. You should have a little over .001 inches clearance between the brass and the chamber walls near the rim and shoulder. With a new case you should be just able to feel the clearance trying to jiggle the case side to side in the chamber.
In the old days they started out with oversize reamers, as they wore they were honed and ground till they were too small to produce a good chamber. Also if the tailstock on the lathe was not centered the IDs of a chamber might be oversize.
I just rebarreled a 30/40 and the old barrel had an excessively large clearance with new brass. The case positively rattles side to side in the old barrel.

[Dick Hosmer]

So far as the group size is concerned, I'd also try a longer range - I'm not sure the bullets are fully "asleep" (completely stable) at only 20 yds.

[Thomassen]

Just for fun I checked the case length after firing. They trimmed at 2.152 inches using my Lee case length trimmer. I haven't trimmed them In two firings. They still measure 2.152, some at 2.154. Max case length is 2.165.


I see no evidence of case head expansion when dissecting my cases. There is no soot on the cases, excepting some on the case neck above the shoulder. This is telling me that cases are expanding to grip the chamber wall. There is no case thinning above the case head (I performed a cut a way to see).
I am perplexed. I also measured how far the primers are backing out.They ae backing out between .014 and .018. I am thinking of trying different brass and primers. I do have some CCI Large military primers I use for my Garand. Would this be to hot to use?

I also spent a couple of hours (really, 2 hours) working at removing copper fouling. Still have residue. I'm thinking of getting some cerrosafe and doing a chamber cast.

Regarding the primers backing out, I noticed the same thing on cartridges used in my US Krag when I loaded for cast bullets. Never saw it when I loaded for jacketed. I am using Winchester LR primers. Am beginning to wonder about slightly under sized primers.

[Thomassen]

I'm wondering what others use for loads in their Norwegian Krags. If I was only getting about 70% load density with 32.5 grains of Varget I may not be getting enough with 35 grains.

Am beginning to think I need to go back to square 1. Change everything: bullet type, powder, brass, and primer.

Posting you load data would be helpful.

Happy New Year!