Mauser 98k Keyholing

DiMP

DiMP

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Took my new-to-me Mauser 98k to the range yesterday. Set up poster board at 25 yards to find where it was hitting and was sad to discover it was keyholing and putting up 8" groups at 25 yards. The barrel has a very small bulge about 3 inches from the muzzle which I knew about before I purchased it. Would this bulge be the entire cause of the keyholing, and if so, is there anything I can do about it? The previous owner told me about the bulge and that it didn't affect grouping, so I'm wondering perhaps he might have been shooting different ammo or something? I'm shooting the PPU 198gr ammo (and I bought the same projectiles) Other than than, the rifling is in good shape, crown looks good, and putting a bullet in the muzzle end it stops about 1/4" shy, so the projectiles are correct sized.

EDIT: I just re-read my e-mail correspondence with the seller, and I may have misinterpreted. The seller said "You saw the small ring inside? Rifle is shootable everything smooth" which I guess I interpreted "shootable" as "it still groups" but I guess I should have read it as "it won't blow up"

So back to my original question then, is there anything I can do? Different bullets make any difference?
 
If you want a shooter, then your options are:
1. Rebarrel
2. Cut off the barrel past the bulge and recrown.
3. Ask if a gunsmith can counterbore the barrel past the bulge. 3" is probably a bit too much to counterbore with a standard lathe setup though. Probably needs special tool bit. But counterboring is probably the best balance between cost and clean job.

EDIT: Also try different bullet weight first, maybe there's one that will shoot.
 
I would get the barrel counterbored. 3” shouldn’t be too hard to do in a lathe. Personally if it was me I would put a long 3/8” endmill in a drill chuck and slowly go until I cleaned up the bore. Other option for counterboring would be a 3/8 drill followed by a 3/8 flat drill.

It would also retain the most originality and from a practical perspective it protects the crown more than a standard barrel.
 
Rifle barrel shouldn't have buldges. In my opinion, there was a barrel obstruction serious enough that caused a Mauser barrel to buldge. Some pictures of the affected area would be very helpful.
 
If you can't do it yourself, take the rifle apart, right down the the barreled receiver and get it counterbored past the bulge.

That way you won't have to cut the barrel back.

I usually drill in appx 2-3 cm past the bulge, which will be gradual, not sharp edged.

This will give you some velocity loss but it will stop the keyholing and if the rest of the remaining bore is decent, accuracy should be good.

All sorts of K98 milsurps that had seen rough use or had a muzzle obstruction had slight bulges that effected their accuracy.

Counterboring was an acceptable measure, under the circumstances.
 
Thanks for the input. I'll try to get pictures up on next days off as I'm away from home for the weekdays currently. I sent a message to one of the guys at work who does gunsmithing work to see if it's in his realm to counterbore the barrel. I will be hanging on to the rifle regardless, and if it becomes just a noise maker, it is what it is.
 
DiMP said:
Thanks for the input. I'll try to get pictures up on next days off as I'm away from home for the weekdays currently. I sent a message to one of the guys at work who does gunsmithing work to see if it's in his realm to counterbore the barrel. I will be hanging on to the rifle regardless, and if it becomes just a noise maker, it is what it is.
Click to expand...

If your guy at work has access to a lathe, it's very easy.
 
So the guy from work doesn't have a lathe, but he's given me a lead I'll follow up with on Monday. I tried my best to take some photos. The bulge is just shy of 4" from the muzzle (the picture makes it look like the calipers aren't lined up with the end of the barrel, but they are). I tried to take a picture down the bore from the muzzle, and although it isn't a good picture, you can clearly see a "missing" section of rifling

K98-01.jpg



k98-02.jpg
 
Brutal.
What's the rest of the gun like? A Russian capture I assume from the way the bluing looks.
Used barrels come up for sale every now and than on the EE. Expect to pay anywhere from 100 to 200 bucks. A brand new Lothat Walther would be great, but it looks like they're hard to come by in Canada. One could replace it at home with homemade tooling.
 
I've counterbored deeper than that on both milsurps and sporting rifles with surprisingly good results.

Brownelle's sells barrel liner drills of different diameters, used to drill out old bores, to accept liners, which they also sell.

SHORT, PILOTED BARREL LINER DRILLSHORT, PILOTED BARREL LINER DRILL
BROWNELLS

(In Stock)

$63.99 - $83.54

These drills are "piloted" on their tips and with CARE, can be used in a DRILL PRESS to counter bore as deep as 12-13cm or six inches.

If your friend is capable, he should be able to counterbore the barrel shown, without much difficulty.

If that barrel is from a rifle with matching numbers and is still in full military spec, it's the route I would take.

You will lose the same amount of velocity as you would by cutting back the barrel but accuracy, from what I can see of the bore, should be much better.

If it's a sporting rifle, you have all sorts of options.

I've also seen and have a rifle with a similar bulge that shoots as well as any other barrel.

It almost appears as if the barrel isn't just bulged but expanded right to the muzzle.
 
Tradex Canada (TEC) has some 98 Mauser Barrels, no 8mm, but ranging from 30-06 to .375, .458 and 9.3 x 62; most are Zastava. They start at 149.00; not sure if these will work for you or not.

https://www.tradeexcanada.com/produits/85
 
There is currently a barrel on the EE I was looking at. What is the process like to remove the old one and install the new one? How does one ensure proper head-spacing after a barrel change? Or is it a "buy barrel and bring to gunsmith" type thing
 
DiMP said:
There is currently a barrel on the EE I was looking at. What is the process like to remove the old one and install the new one? How does one ensure proper head-spacing after a barrel change? Or is it a "buy barrel and bring to gunsmith" type thing
Click to expand...

If you have to ask, take it to a competent gunsmith.
 
DiMP said:
There is currently a barrel on the EE I was looking at. What is the process like to remove the old one and install the new one? How does one ensure proper head-spacing after a barrel change? Or is it a "buy barrel and bring to gunsmith" type thing
Click to expand...

You need a barrel vise and an action wrench to start with. The threads may need to be set back to get the headspacing and indexing of the sights correct. If you're planning on taking the sights off your barrel and moving them to the new one, that's another can of worms that involves solder and a lot of heat.

The cost of the barrel vise and action wrench alone would make it worthwhile to go give somebody else the job, unless you're planning on taking up home gunsmithing as a hobby.
 
Well, I just got off the phone with the gunsmith. They bore scoped the barrel and based on the bulge say that it is not a candidate to be counter-bored. I sent a PM to the seller on the EE who had the barrel for sale and said I would take it. I am going to get the EE seller to mail the barrel directly to the gunsmith and hopefully with that I will end up with a properly working firearm. I'll be using this as a learning experience and being even more cautious when buying guns online...
 
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