Head spacing a krag

[webradbury]

I'm starting a krag project and was wondering about the head space. There is a shoulder machined into the receiver and looks to me that one would simply thread on the barrel and tighten it down until the extractor groove is at 12oclock. Is this the case?

[madsenshooter]

That's the case. Headspacing is on the rim. You don't need go or no go gauges, you don't have to worry where the shoulder winds up, your only concern is that the distance from the front of the rim to the boltface doesn't exceed .070". A "field" gauge would be all you need.

[Der Gebirgsjager]

The above is absolutely correct. But--the barrel, as noted in your post, can only screw in just so far because of the shoulder. So what you might run up against is that even with a new rebarrel job you will have excess headspace. The situation can often be corrected by swapping in a new bolt body. Over the years the guns were all fired untold thousands of rounds by the military, then sold to civilians who cut them down for sporters and fired hot reloads in them. The result is that more often than not the one locking lug has set back and poor headspace will result. Some are more so than others and often the bolt from another rifle or one picked up on e-bay will solve the problem. In fact, occasionally there are unissued bolt bodies still in the grease for sale that will solve almost any headspace problem.

[WILCO]

I'm starting a krag project and was wondering about the head space.

For $22.00 you'll have your answers:


https://www.midsouthshooterssupply.com/item/00070BG3040F/30-40_Krag_Field_Length_Head_Space_Gauge_

30-40 Krag Field Length Head Space Gauge

Every gunsmith knows that proper use of a headspace gage is the most reliable way to test the length of a rifle chamber. "Headspace" is the distance between the face of the breech and the base of the cartridge when the action is closed, and excessive headspace can be dangerous as well as impair accuracy. For instance, unsupported brass fired in a rifle action with excessive headspace can rupture, allowing gas to blow rearward like a rocket exhaust. Because your safety is on the line, Forster Headspace Gages are made with painstaking care and exacting manufacturing standards to ensure accurate testing of your rifle's chamber. If a rifle closes on a GO gage, the rifle chamber will accept any ammunition that is made within S.A.A.M.I. (industry standard) specifications. If a rifle closes on a NO GO gage, the rifle chamber might have excessive headspace. Most gunsmiths chamber a rifle's headspace between the GO and NO GO dimensions. If a rifle closes on a FIELD gage, the rifle chamber is dangerously close to or already over the S.A.A.M.I. specified maximum chamber size.


FORSTER RELOADING PRODUCTS

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Price: $21.86
Item: 070-BG3040F

Some other links for you:


http://www.practicalmachinist.com/vb/gunsmithing/head-space-krag-266334/

http://forums.thecmp.org/archive/index.php/t-96856.html

http://thefiringline.com/forums/showthread.php?t=398937

[webradbury]

Been away polishing metal parts...sorry. I have a (what was advertised as) unissued bolt body, (supposedly unissued) receiver and a new repo barrel from Numrich (which is beautiful). I screwed the barrel into the receiver when I had a few minutes after it came in and it stopped with the extractor notch at the 1 o'clock position (looking at the breach through the receiver of course). With the info from above and the new parts, it should tighten down and work safely I am thinking and hoping.

I've done firearm repairs before (for myself) but haven't changed a barrel or built any projects as you all can probably tell. But I'm learning and having a fun time. Thanks

[webradbury]

Finally got set up to install the barrel and got it headspaced OK. The action nut Buckshot made for me is awesome and worked like a charm.

I now have another Krag project planned after this one is done. I bought a cut down Krag from a member here. It's in good shape but I checked the headspace and it closes on the field gage. I have to figure out what to do to correct it...probably a new bolt body. I need to check this with my other bolt from the ongoing project.

[madsenshooter]

One thing you'll run across with Krag rifles is bolts that have had the locking lug lapped so that the guide rib will bear on the receiver. Friend of mine was taking a gunsmith class. He thought it would be a good idea to do that. He lapped a new bolt body in so that it would bear. Then he found that the new barrel I sold him, with that now ruined bolt, gave him excess headspace. He got another body, I got the lapped one here somewhere. It appeared the lapping took very little, if any, out of the locking lug in the receiver, most all came off the lug on the bolt.