1898 Krag Chamber question

[jugulater]

A good while back i started a thread about a Sporterized Krag Carbine that was a family heirloom, I gave that gun to my uncle along with a note describing the issue it had and now it proudly sits on the wall in his living room.

This thread is about something I noticed that the Sporterized Rifle i bought to fill the Krag sized hole in my collection has been doing to my brass. The gun appears to be pushing the shoulder forward and creating a much sharper shoulder. i know this gun has had work done to allow the guide lug to engage on the receiver, and my thought is that this has caused it to have a headspace issue.

is this a headspace problem or simply a oversized chamber?

i have included images of the gun and a comparison of a unfireformed case next to a fireformed one (it turned the picture sideways for some reason).

[13Echo]

Krag chambers are big. Mine headspaces just fine and the shoulder blows forward. If you want to have any kind of brass life just neck size and don't worry about if.

Jerry Liles

[Der Gebirgsjager]

Just a matter of terminology I guess, but to me it looks like the shoulder is being pushed back rather than forward. I do see the sharper shoulder.
Looking at the brass, I don't see any sign of stretching just forward of the rim on the case, a sure sign of excessive headspace. So, without having the gun to examine, I would opine that you do not have a headspace issue, and that it's just the unique shape of your particular chamber. In any event, it's not to worry. Just neck-size-only your fired cases and go with what you've got. I wonder if perhaps your rifle wasn't rebarelled or set back following the bolt work--which would account for the chamber.

[jugulater]

i had not thought to check for any signs of the barrel being set back, thats something i will check when i am able to.

ill go ahead and put down to neck size only in my reloading notes for this gun. This Krag is one of my favorite shooters due to its accuracy and the smoothness of the action.

The only bad thing about my Krag is that when i miss i cant blame it on the gun...

[Scharfschuetze]

I think that it's normal to see shoulder variations in the Krag's chambers. As far as US Ordnance was concerned the critical headspace measurement was the depth of the rim. The British 303 is the poster child for this approach.

Here is what my 30/40 Krag brass looks like after neck sizing. You can see that my shoulder is slightly different from yours and it is certainly different from unfired factory new cases.

[13Echo]

On rimless, which headspaces on the shoulder, case stretch rings in front of the web is a sign of excessive headspace. On a rimmed case, which headspaces on the rim, such a stretch mark is a sign of a big chamber.

[gnoahhh]

Lapping the single Krag locking lug so that the safety rib/lug bears too was not an uncommon practice "back in the day". But, there is a caveat: by doing such, you remove the outer layer of carburized steel on the back surface of the main lug, exposing the dead soft steel under there. I can't imagine but that increased set back with repeated use would be the result, or at the very least fast wearing of that surface.

I bet the barrel was set back after the bolt alteration. The safety lug typically has many thousandths of an inch clearance behind it, and excess headspace would be a result of moving the bolt back to take up that space. Whether a case headspaces on the rim or on the shoulder doesn't matter, excess headspace is excess headspace. Obviously the smith set the barrel back and re-reamed the chamber, hence the somewhat strange case shape. Looks to be a well done job in any event. I would neck size only after initial firing, and call it a day.

One gun you do not want to mess with if it has excess headspace is a Krag. Letting the cases repeatedly get a running start at battering the bolt head of a gun with but one locking lug (made from relatively brittle carburized low carbon steel) will soon call the safety lug into play. On a happier note, the design of the Krag is such that it is nigh impossible for the bolt to blow straight back out of it in the event of a catastrophic failure. The safety lug will either stop it or twist it out of the way to the right.

[jugulater]

after looking over the gun i found the witness mark on the receiver, but none on the barrel. the gun shows no sign of excess headspace or undo wear caused by excessive headspace. im certain that the modification done to the gun was as described above, and i thank everybody who responded for helping me answer some questions i had about this old girl.

now i can get back to shooting!

[madsenshooter]

gnoahh mentioned the not too good habit some had of lapping the bolt lug. I saw one lapped Krag that the rear of the receiver, where the guide rib was bearing, cracked. The only thing bearing was the guide rib. A Lt Col friend of mine, while taking a gunsmith class, though it would be a good idea to lap the locking lug. It all came off the locking lug and not the locking recess, thankfully. He had too much headspace with the lapped bolt, which was a new one by the way. I have that bolt, in case I ever need to make Krag brass from a cartridge with a .070 rim. The Lt Col got himself another new bolt body and didn't lap it. I always had to keep my Lt Cols in line! It's kinda tricky getting them both to bear without going overboard. Bolt stretch over the years has made a lot of them fit that way.