Problem with chambering new brass

Ammunition, reloading, shooting, etc
FredC
Posts: 1991
Joined: Fri May 31, 2013 4:38 pm
Location: Dewees Texas

Re: Problem with chambering new brass

Post by FredC »

I do have a couple of NOS bolts for sale, not sure if they would do Zac any good as I do not think his bolt has any appreciable wear. I think his Krag has been sitting in closets since assembled by Stokes. I do have a bolt measuring jig if he wants to send his to me to verify his measurement and see if my bolts are appreciably larger. This has been a journey but I think it answers conundrums we have had over the years.

Just to clarify reaming a Krag, the rim should just touch the barrel with no recess in the barrel from the reamer. One could fabricate a thin washer to ride on the reamer and stop its progress when the reamer contacts the barrel end. I did this with my sporter after PTG sent me the corrected reamer. I did not want to alter my "perfect" headspace but just enlarge the diameter ahead of the rim.

Zac could look in the lug recess in the bottom of his receiver and see if the reamer removed material from the barrel face. A scribe slid across the surface would give you an indication if much material was removed. Your photo on page 2 shows that area very clearly: 20210407_204140.jpg (325.9 KiB). Not sure how Br copies and edits photos, but just look at the bottom of the bolt race and see if the reamer rim area touched that surface. If not you may be dealing with out of tolerance brass.

Zac952
Posts: 159
Joined: Wed Apr 07, 2021 1:37 am

Re: Problem with chambering new brass

Post by Zac952 »

Thank you FredC I will check my chamberface, although I do believe that it likely did remove material from the chamberface, I appreciate all of your hard work in verifying the information and I will take a look at my forster gauge when it comes in and let you all know whether it looks like it is better tolerance than the Clymer, this has been quite the journey and has been a wealth of information for me and hopefully for others as well.

So to sum it up as well as I can, Clymer gauges seem to have too large of rim to properly headspace a Krag, the maximum rim diameter of a headspace guage at the rim should be .543, be sure to double check that it sits flat in your bolt head recess first, and a thin washer may be used to prevent a reamer from cutting in to your chamber face.

Hopefully these are the correct conclusions I have drawn here and this will both help me and others in the Krag community to chamber their barrels correctly!
Also FredC may I use your CAD drawing to send to Clymer to possibly give them an account for how a Krag headspace gauge has ought to be?

FredC
Posts: 1991
Joined: Fri May 31, 2013 4:38 pm
Location: Dewees Texas

Re: Problem with chambering new brass

Post by FredC »

Feel free to use the drawing and link to this thread. We do this for knowledge and grief prevention. I would say that gauge should have a rim diameter not greater than .535". My .543 was an average of 3 bolts, we do not know the armory's original tolerance.

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butlersrangers
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Joined: Wed Oct 07, 2009 11:35 pm
Location: Below the Bridge, Michigan

Re: Problem with chambering new brass

Post by butlersrangers »

FWIW - The rim diameter on my 'no brand' Field Gauge varies from .534" to .536".
The Gauge's rim edges have a slight radius or 'bevel'.
(I bought this gauge, years ago, on ebay. Whoever made it, IMHO, understood the Krag breech and the Krag's 'flanged' bolt-face).

The rim diameter, on a sample of several new Winchester .30-40 cartridge cases (measured today), varies from .535" to .536". (A gauge with a larger 'rim' diameter than .536" seems to make little sense).

I agree with 'FredC', that a quick glance or 'feel' should reveal if the 'finishing-reamer' removed any metal from the barrel breech.
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Zac952
Posts: 159
Joined: Wed Apr 07, 2021 1:37 am

Re: Problem with chambering new brass

Post by Zac952 »

Yes there was some cutting into the breachface, still haven't got my field gauge yet, but I will still check it with that. Unfortunately I think I may need a new barrel, not sure if I'll go new or used buy I'll definitely check out that thread on barrel removal and figure out some proper gauges to chamber it if necessary. Still looking forward to shooting a Krag for the first time, aside from the three shots I took into the bank to test it the other day.

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butlersrangers
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Location: Below the Bridge, Michigan

Re: Problem with chambering new brass

Post by butlersrangers »

A clear picture of one of your 'fired' cartridge-cases can reveal a lot.

Gauges?!!! We don't need no stinkin Gauges!!!
Last edited by butlersrangers on Wed Apr 28, 2021 7:02 pm, edited 1 time in total.

FredC
Posts: 1991
Joined: Fri May 31, 2013 4:38 pm
Location: Dewees Texas

Re: Problem with chambering new brass

Post by FredC »

Still the temporary fix offered by Parashooter with the loops of mono filament line or looking for some Remington brass with the .061 to .063 rim thickness.

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butlersrangers
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Location: Below the Bridge, Michigan

Re: Problem with chambering new brass

Post by butlersrangers »

Better than Duct Tape .... the Genius of Parashooter!

We want a Range Report.
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Zac952
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Re: Problem with chambering new brass

Post by Zac952 »

20210428_200259.jpg
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20210428_200248.jpg
20210428_200248.jpg (553.1 KiB) Viewed 101349 times
Some pictures of my 3 fired brass, the primers are backed out about .015,

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butlersrangers
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Re: Problem with chambering new brass

Post by butlersrangers »

'Zac952': IMHO - Your brass does not appear 'stretched'.

It is possible your loads were so mild, just the primer was pushed back to the bolt-face. There is no apparent 'stretch' of the case side-walls. The case Head was not pushed rearward to the bolt face.

The measurement of your cartridge rim thickness, added to the primer protrusion, would probably give you a good read on your Krag's 'head-space'.

(FWIW - I measured some of my 'fired' .30-40 brass. These had been full-power loads. 'Primer protrusion' was hardly noticeable and measured approximately .004" to .005". There was minor sidewall stretching near the case head).

I really think you should try some full-power loads, with the cases held-back against the bolt-face, with monofilament 'spacers'.
With the case 'head' supported by the bolt-face, all case expansion & forming will be forward into the chamber.

By 'neck-sizing' your 'fired' cases , you only need to do the monofilament spacer onetime. Your brass will be custom fitted to your chamber. (Headspace will not be a problem).

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