Mauser 98 Action Truing

Good day everyone,

Hoping to get a little info very specigic to Mauser 98 Action Truing.

Currently I use a Gre-Tan Action Blue Printing Jig.

Question I have.
1. Which Alignment Mandrel to use along with Bushing Kit for the typical large ring Mauser 98 Action.

Thankyou all in advance.

If you're just doing one (or two, or three) actions, it's simple (and a hell of a lot cheaper) to just turn your own mandrel. Get a rough idea of the bolt raceway diameter with a telescoping gage, then creep up on the OD and keep test fitting until you get a snug fit of the mandrel in the raceway.

Careful “ truing” a Mauser Don’t recut the threads or the bolt lug seats, these are case hardened and you can easily get into the soft metal and cause setback. Lightly lap the lugs only for decent contact not full.
As stated before make a mandrel that threads into the receiver, clean up the receiver face. If you want to clean up the barrel seating face, you’ll have to get creative and use your gre tan jig.
FYI when you thread the tenon, remember the barrel seats against the interior face not the outer face, you should have about a .002 gap between the barrel shoulder and the receiver face

In my humble opinion, don't bother, it is a waste of time for what benefit you will get

I did a Norwegian Krag, trued the face off the original thread, seating on both. In reality, you have no idea whether it really is. Torqued up with about zero rotation. And I doubt it matters. Bigger challenge was making an action wrench. But now I've got it just in case I ever wear the barrel out, or need to take a couple pounds off it so I can actually shoot it without my entire arm going numb.

A CZ 223 I did seats internally, I think, couple years past. Just the way it is, use it, get on with life.

Limited experience with military actions ... but they've typically been *BETTER* than a production action from a bad era ... some of the older 700's ...

Latest 700's I did with the ugly dot-peened logo's and SN's have been really good. The SS version was quite hard, and cut really nice. I like ...

Jim Kobe said:

In my humble opinion, don't bother, it is a waste of time for what benefit you will get

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Jim is pro.
I am an amateur.
My opinion is MORE humble.
I gave up truing Mauser actions 20 years ago.
Here is 1903 Turkish Mauser I built last year in 260.
I sighted in shooting a 1/2" group at 100 yards.
It shot a deer.
This Mauser was not trued.
I have a number of other examples like this.

wesg said:

...Bigger challenge was making an action wrench. ...

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1903 Springfield ring is same diameter as US Krag. Action head for one will work. Is Norwegian Krag different?

Hey Ken,

No idea, never messed with a US Krag or Springfield. Off the top of my head, there was 'stuff' in the way I wanted to avoid. And I think I wound up with a key to engage something? If I remember, I'll get a picture next time I'm back.

Only real difference is it's a left hand thread. But 10 TPI from what I remember.

Old 'Bud'. Box of parts he found in his garage. Put a Shaw barrel on it, 6.5x55. Shot well. Miss him. A lot.

The only other 'surplus' action I've trued up is a No4 Enfield. And it was far better than most of the Remingtons I've done.

I have done quite a lot with Mauser actions and the advice given above to just go shoot it is good, I know, we really like tinkering and sometimes you can get out of your depth or just go too far. This is from a rifle brought to me some years back, I keep it around as a sort of demonstration piece as to what can happen if you become over ambitious, the guy was "sporterising" a Mauser and decided to modify the bolt handle by chopping it off and welding it back on at a more favourable angle, not pretty:

THAT was "more favourable?"

That Gre-Tan action blue printing jig is just a spider to fit into a lathe chuck. If you own a lathe you could have made your own spider. I have sporterized several Mauser's. here's my advise: if the receiver threads are boogered up - clean them up with a 98 action tap. Do not attempt to reface the C ring with a boring bar or other single point tool. The interrupted cut will cause chatter so bad that it will make the barrel seat face way worse than it was. If you need to true or reface the C ring make a lapping tool and use valve grinding compound. If your working with an M38 Turkish receiver and want to remove the lip on the front of the receiver that holds the hand guard , make a turning mandrel and make that cut between centers. If there's any 'slight' binding as you cycle a stripped bolt, apply a very small amount of fine lapping compound and work the action just enough to smooth things out. Do not grind or machine through the case hardening.

There's not much else that needs to be done to improve these actions. A Mauser is supposed to be loose up until the action is closed. Once closed it should be tight as a drum. They were designed to work while under the roughest of conditions. As for improving accuracy; the first 98 that I worked on (many moons ago), I went all out to do every process that I thought would increase it's precision. Then, just last year I took a rusty 1908 Brazilian receiver, cleaned it up, added the action parts from a Hodge-podge of 98 parts I had laying around, put a "new - old stock" 1909 barrel on it with some no name 98 stock from a surplus place. Both rifles are just as accurate. Blue printing a Mauser receiver really isn't necessary so long as it's a sound action.

When I've rebarreled Mausers with "modern" contour barrels that are close to full diameter of the receiver I ignore the inner shoulder. It's needed on military contour barrels because there isn't enough OD for a sufficient torque shoulder at the receiver ring. I see no purpose for it otherwise.

There's nothing that makes it fundamentally different from every other bolt action barrel that uses a single barrel torque shoulder IMO.

I don't pretend to be a gunsmith but back in the day I would put the end of a 98 barrel in a 4 jaw adjusted to near zero, and the barrel step diameter in a steady and taper turn the barrel steps to longer tapered steps using the taper attachment for a nicer looking barrel. Then polish the whole OD length with crocus paper. the small portion ahead of the front site I would not bother with except to polish it up to match that finish on the barrel to dead smooth, or to fine circle lines from the grit size of the abrasive cloth.
Yes, good to remove the trigger when doing this because it is easy to get whacked by the trigger.
Turning bolt handles I would send out to a fellow who did a nice job of that.

My appologies,
I should have clarified a bit more.
This action is a NEW Mauser 98 large ring, from Mauser.

I appreciate the help and guidance.

Although I may not be a pro, or have the experience or reasoning of others... I do have a very real life experience and understanding why all dangerous game Guides carry Mausers or Weatherby, NOT Rem?????. Some wont allow "Other Bolt Rifles" for very good reason.. never thought Id see the day a round falling out of the chamber of one of the other hunters, then panic from an angry hippo.

I dont mind so much rounds falling from the action.... its loading another round then the round going off without touching the trigger thats a bit unerving for my liking. But to each his own.

Thank you all again for sharing your time and expertise. I am greatful

A new action?

Why do you think it needs to be trued at all?

I would start with the "Make your own Mandrel" suggestion, and do your measuring to see IF it needs the work, before I would get all concerned about much else.

trevj said:

A new action?

Why do you think it needs to be trued at all?

I would start with the "Make your own Mandrel" suggestion, and do your measuring to see IF it needs the work, before I would get all concerned about much else.

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To be perfectly clear, things have changed in the last hundred+ years. Stuff that was being produced by essentially a small step up from "Craft Labor", on rows of manual machine tools, where very few among the operators, knew more than enough to feed the machine parts and crank the levers, really DID need to be trued, while a lot of modern producers (though not all!) have filled their shops with machines capable of far better than most can measure, and with people, far more capable than many ever imagined would become available as labor!

I have a factory-new-bought, 1958 Model 70 Winchester, and, as you get right down to it, and go through it with an experienced eye, you really do start to see why there were gunsmiths in almost every small town. Frankly, the quality of goods being produced, was pretty crappy, and there was a LOT to be done to improve upon them!

If you watch the posts by some of the guys here that are hard in to Production Machining, they say to have failure rates in the tenths of a percentage range, when things are going poorly, at far far higher tolerances than were expected off the lines at Winchester, say, in the 50's and 60's. One or two tenths of a thou, vs. plus or minus 5 thou or more.

It is true that the best chuck. even the best 4jaw won't get near .0001 for run-out and wobble.

I don't own such a jig, but they are pretty cool.
I have three 98s and I bet that the locking lugs are better than .0005 likely near zero now well broken in with use, and all still snug a new case with a feel at closing.
One has a replaced barrel so the gunsmith who fitted the breach did a very good job of it. One day I might micrometer a bullet before and after shooting it.

Ratfink said:

I do have a very real life experience and understanding why all dangerous game Guides carry Mausers or Weatherby, NOT Rem?????. Some wont allow "Other Bolt Rifles" for very good reason.. never thought Id see the day a round falling out of the chamber of one of the other hunters, then panic from an angry hippo.

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A lot of hunters killed that way yearly in Africa?

I love mausers and have several but I suspect the whole dangerous game/controlled round feed is much overblown.