Help from the Mauser Experts needed

Hi guys
I was on the range with my “new” Kar98a
1 shot and the bolt was impossible to open.
Riffle taken apart and bolt open with a steeltube.
Chamber pitted in a place not easy wissible.

Now question 1
Is it possible to repair safe or do I need an other Barrel
(Not easy to get)

2.: is it possible to turn down a K98k barrel to kar98a
Contour ?
What about tread size.

The rifle is bought as a shooter.
And I have technical skills to do what needed.

I also have the opportunity to deliver the rifle back

But I have to chose Repair or return it.

So I need a little advice from you guys

Jsne

If your chamber is pitted then it's hooped in that caliber. The only way to repair that would be to rechamber it in a caliber that would eliminate the chamber completely and then the bore...well, would create a wildcat cartridge. To have it in the caliber and configuration you want for original you need a new barrel.

A replacement K98a barrel in good shooting order may be considered to be unobtanium. You're about a century too late to find a new one.
If a barrel should turn up, it will have been removed from a scrapped rifle, and likely to be in doubtful condition itself.

Send the rifle back, and spend your time and money on something better.

Hi all

Thanks for advices

It seems to went out best way😀

The dealer have a original kar98a
barrel in good shape.
He will send it so I can look at it and try
It if i want.
If i wont work out. He take it all back
With no cost from me.
And if there is any problem with
Headspace he will cover any cost
To let a gunsmith fix it.
Or I can return the gun as it is for now.

But i still want a Kar98a to shoot in our
Historical shooting club.

I think it is a very fair dealer👍👍

Jsne

Let us know then, the new barrel shouldn't be too bad to install...

The bad one is removed.
Waiting for the other one later in this week😀
With a little luck it will be ok.

As long as the chamber is clear, the bore will be worn I expect but you can work with it. You want to shoot it anyway...

The other one was also 101 years old
So with a little luck the bore in the new one
Will be Ok.

In Denmark where I live you can not collect
These kind of weapons.

Only get license for hunting or competition.
Many “ elegal waepons from both world wars
Had been chup up for parts.
So spare parts not always means worn out parts

Man, jsne you are lucky!

Give us a look after...

If any interest pictures of case an old barrel.

I looks like someone have tried to remove a ruptured case
With different "wrong tools"
An beside this there also a hole in the chamber.

Sorry for Chamber pictures. It is not easy to take.

Tremendous swell to the cartridge, looks like someone tried to change a tight chamber or change the caliber...maybe tried to polish without any actual knowledge of how. Anyway, yes...that barrel is hooped.

Yes
Good thing is
Already have the other Barrel
Chamber fine.
Rifling is as good as the old one. Not new but Ok for shooting
Historical rifle shooting
After all, it is 100+ Years old
And what are the change to just call a guy
An order an replacement for a 1918 kar98a and get it in two days😀

Start to fit it tomorrow.

Jsne

Hi all

Now "new" barrel instald.
Headspace ajusted, Sight calibrated.

All done with a Original Kar98a Barrel in 4 days from I realice there ´was an issue with the rifle.

Range report will follow in a coupel of weeks :-)

JSNE

A very hard to find rifle restored and looks great. Yes, looking forward to range time.

Astonishing, jsne, you really are very lucky!

Not that lucky :-(
Here are a disappointing range repport
Fires about 30 round
Maby 8 to 10 hit the target all over the place.
Distance 200 m
Different ammo with mo help.

But chamber fine 🤪

Bore looks not that bad
I will now slug the barrel and see if it oversized.

I can still return the rifle. But will be sad to do it.

Will report back with the result of the Sluging.

Jsne

Quote:

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Originally Posted by jsne

I can still return the rifle. But will be sad to do it.

---

Has to be a bullet size problem. You could cast and gas check a larger diameter bullet I should think. Let's see what the bore measures out at?

I have now slug the bore

.3257
I got prvi .327 (actually .3265)

I an aware that it is on my own risk

But opnion on if is is safe to use this bullets?

Jsne

Quote:

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Originally Posted by jsne

safe to use this bullets

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Here's something written in a local hunting forum... Thing is, your bore is big enough to take them. I'd be with you...and try them.
Sounds like before you had .318 diameter bullets and they were barely engaging.

Both vintage military and sporterized versions of the Mauser Model 1898 bolt action rifle are still readily available on the used gun market but, it should be noted that older versions of these rifles are designed to fire a .318 caliber bullet and these rifles are designated as having “J” bores whereas, newer versions of these rifles are designed to fire a .323 caliber bullet and these rifles are designated as having “S” bores.
American-made 8mm Mauser ammunition is commonly loaded with .323 caliber bullets but, is designed to generate significantly lower chamber pressures than standard European loads so that the .323 caliber bullets can be safely fired in older .318 diameter J bores without generating excessive chamber pressures.
Doing so does limit the ammunition’s performance due to a lower muzzle velocity.
Modern, full-powered, European manufacture 8mm Mauser ammunition should never be fired in vintage Mauser Model 1898 rifles unless you are certain that the rifle has the .323 S bore diameter.

Thank you😀
I will load some with .327 bullets and see if it will
Work.
If this will solve the problem I leave it with that.
Otherwise I got a k98k barrel from a friend
So Maby I will turn that in Kar98a contour
An see how it will work out.

Jsne

If you use boattail bullets, that alone can cause wild shots in a old rifle with a chamber designed for Spitzer bullets. The transition cone in old Mausers is often very long, so, quite apart from the correct diameter, you need a bullet with a long cylindrical section, so that (hopefully) the bullet engages the lands before the base has left the neck of the cartridge case.

Make the usual test of maximum possible seating depth. You will quite possibly have to seat the bullet as far out as it can reasonably go, i.e. leaving a minimum length equal to 1 caliber in the cartridge case.

Thank you for the adwice.
I have some bullets pulled from 8x58RD (Danish Krag)
The are .323 and flat.
I will try to load some with them along with some
With the .327 and what happens.
There will go a couple of weeks before I have
Time to try them

Jsne

Good luck, and let us know how you get on!

I'm also watching...from a distance.

Hi again
Today I wass on the range with my Kar 98a.
To Patric and Jim. Both of you are spot on:-)
Patric. The flat base bullets does the job. I learned some new here. Thank you.
Jim. It was a bullet size problem the .327 boat tail worked fine as well. thank you.

picture. 5 group high flat base. 5 group left .327 boattail (sight lowered a little)
10 group first 5 flat base 5 last .327 boat tail.

I thing i went very well:-)

Distance 200m prone with no support.

Jsne

Only thing now: I just got two good K98k barrels. Maybe I still want to turn one too Kar 98a
contour and use it to so I dont need "special" ammo for this rifle. HMMM
Or maby I leave it as it is. HMMM

Looks like it shoots now... I agree with standard ammo. You don't have a pure rifle anyway so if you can contour the barrel to match and looks good you already are way up on many of us that don't even have that model of rifle. There are less and less it seems...

Most rifles have 'special' ammo, as they all prefer some loads. As you load your own it isn't a problem, it is only when you can get surplus that it is a problem.

You are right.
But i have 7 mausers I am shooting.
And having a load with oversized bullets
Can be potentially dangerous.
You know morphus laws.

Jsne

I guess you are referring not to morphus, whoever he may be, but the famous Edward Aloysius "If anything can go wrong, it will" MURPHY. If my memory cells are still ticking over correctly, in the postwar years Murphy - yes, he really did exist - was involved in research using rocket sleds to develop ejection seats. The apparatus was, of course, well equipped with a battery of sensors to measure the stress on the seat and the test pilot. After one particularly stressful test the pilot inquired how the results had turned out.

There were none. Not just one, but every single sensor had been wired up incorrectly.
Someone is supposed to have said "Ah well, that's Murphy for you!" - and the rest is history.

Ok, there is doubtless a certain amount of "urban myth" in the story, but if you search the internet you should be able to find something about it.

[QUOTE=browningautorifle;457667]Here's something written in a local hunting forum... Thing is, your bore is big enough to take them. I'd be with you...and try them.
Sounds like before you had .318 diameter bullets and they were barely engaging.

Both vintage military and sporterized versions of the Mauser Model 1898 bolt action rifle are still readily available on the used gun market but, it should be noted that older versions of these rifles are designed to fire a .318 caliber bullet and these rifles are designated as having “J” bores whereas, newer versions of these rifles are designed to fire a .323 caliber bullet and these rifles are designated as having “S” bores.
American

A lot of incorrect information here. The German military NEVER used a .318 groove bore size . The German military never called any bore size J or S . The actual bore size on any German military rifle from 1890 1/2 was .311 with a groove size of .321 until 1896 1/2 when it was changed to .323 + , called the Z bore change by the German military . The bore size of .311 was always right on but the groove size could [ and did ] vary from .323 up to .326 . They did not care about the groove size as long as it was above .323 . The S BULLET was made at .321 with a .323 skirt so it could work in all rifles , .321 and .323 . It had a open flat base to let it expand to seal with the larger groove rifles . So for modern shooting with modern bullets a flat base bullet or a larger dia boat tail is needed for accurate shooting . The land dia is more important than the groove to get a good bite on the bullet , so a long round nose [ lots of bearing surface to stay straight in the bore ] .323 bullet with a flat base will solve most .325 + groove barrel problems .

Quote:

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Originally Posted by bob q

A lot of incorrect information here.

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Sure thing, whatever you say. Not written by me in the first place, at least I told him that. As always, you're the expert (You say)...

Well I guess all my original German test documents , 80 Gew-88 rifles , original ammo are not real ?

Ok
What I need to know:
If i have a load with .327 bullets and in a mistake
Load them in my smallest Mauser .3225
What could happen?
I always full size my 8x57 not having trouble with
Any of my Mausers.
Yes I could neck size and mark this to avoid any risk

Or I could fit a barrel on the rifle who not have
This “problem”

The rifle is bought as a shooter and not a collectible item.
And I still have a original barrel for it.

Jsne

Q: If i have a load with .327 bullets and in a mistake Load them in my smallest Mauser .3225 What could happen?

A: A very serious overpressure - maybe chamber ringing, maybe shattered action.

I hope someone can help me. I am Tagging onto this thread. I have a K98 all matching numbers J P Saur 1940. I have a set of bore gauges and want to know the correct bore diameter and degrees of wear to the point of being worn out. Currently the bore is measuring 7.95mm or .313. Thanks for any help and advice.

"Correct" is not a word that you will find in standards documentation, but a somewhat subjective adjective, popular with collectors, that already implies a judgement.

The "Masstefeln für Handfeuerwaffen und Munition" - which is the legally binding set of dimensions that would be used by a proof house - gives the following
for the chambering 8x57JS:

Felddurchmesser (diameter across lands) 7.89mm
Zugdurchmesser (groove diameter) 8.20mm

These are minimum dimensions.

It seems that your bore is seriously worn. I have not yet found any official definition of maximum land and groove diameters. Until they turn up, let's look at it from a practical viewpoint.

"Shot out" is not an official definition that you will find in any set of standards. But for a specific rifle it may be defined as that level of wear at which the rifle no longer performs satisfactorily. There are perhaps 3 major factors. A badly worn barrel will usually have a combination of these factors.

1) Throat erosion. Results in the bullet having a free flight before it properly engages the lands. Since the cartridge neck has some play in the chamber, it sits on the bottom, and the bullet emerges in the lower portion of the space available. It is thus engraved on the skew and will tend to have a corkscrewing motion when it leaves the barrel. Depending on the amount of wear, this can result in anything in the spectrum enlarged grouping through keyholing to missing the target entirely at what would be considered point-blank ranges. Hence the general advice to keep the bullet seated as far up the throat as is sensible, and to avoid boat-tailed bullets in military rifles, as these rifles tend to have generous throats by comparison with modern standards. A standard test method is to drop in a bullet of your choice into the throat and measure how far it enters the barrel, i.e. to measure the overall cartridge length that would be required for the bullet to engage before it has left the neck of the cartridge If that position is beyond the max. OAL of the cartridge, then you have a problem. Mauser rifles generally have a very long throat, so you need to look for a bullet with a long cylindrical section. Don't forget that the designation 8x57JS stands for 8x57 cartridge for Infantry (the J) rifle using S (spitzer) bullets. Not boat-tails!

2) Enlarged land diameter. Reduces the engagement of the bullet in the rifling. No immediately disastrous effect until the stage is reached at which the bullet is no longer being grasped by the rifling and is stripped by the grooves without being rotated. With lead bullets this results in immediate serious leading of the barrel and disastrous grouping, as you are effectively firing a smooth-bore gun. I have not experienced this with jacketed bullets, but I have experienced it with copper-plated bullets, with recovered bullets showing that the copper had been stripped off the lead.

3) Enlarged groove diameter. Assuming that all other things are equal - which, in practice, they never are - this allows blow-by of hot gases and is a factor in increasing throat erosion. With jacketed bullets, the only remedy is to use a bullet that is as close to the groove diameter as possible or even a tiny bit (0.001") larger. This trick is limited by the available space for the cartridge neck in the chamber. With lead bullets you have more freedom, as they upset to some degree in the throat, so that even if the largest possible bullet is too small, you can gain a bit more obturation by using a slightly softer lead alloy.

Summarizing:
a) Measure the groove diameter.
b) Select a bullet that is equal to this diameter or + 0.001
c) Select a bullet that has a long cylindrical section, to keep the base guided by the cartridge neck as long as possible
d) Check that you can actually chamber a cartridge loaded with such a bullet.

I hope you can find a solution!

Patrick

Very late, but thanks very mcuh for your reply. I have to conclude the barrel is worn and needs replacing!!