Let's say for instance that I have an 8mm Mauser 98 sporter, but I had an interest in rebarreling and rechambering the rifle for something else. What can or can't I do with it? Would it be possible for me to make it a .308? Would I be better off simply leaving it alone?

Part of the reason I ask is due to the reading I have done recently regarding the 8x57, and apparently there is a difference between old and new in regard to the diameter which can cause excessive pressures in the more narrow of the two if the ammunition isn't correct for that particular rifle. I don't know which one I have - aside from that, I think it would be neat to make it into something else if I could.

All information, advice and comments are welcome in advance.

I'm not a gunsmith, but .308 should be easy. The .308 is a bit shorter, so no magazine lengthening is necessary, and the bolt face is the right size. Checking the bore size is easy. Get an unplated 00 buckshot pellet or three. Clean and lightly oil the bore. Tap the buckshot into the muzzle and push it through the bore with a cleaning rod. Measure it with a micrometer, not a cheap caliper. .323" bores are good, .318" need careful loading. If it's much oversized, say .327", you might be better off rearresting.

Bye
Jack

Jack - thanks. I've got some ammo for this rifle reloaded by my father, and it's a fairly stout load based on what I looked up. I just think that it would be neat to make this rifle into something else.

So what is the process for rechambering a rifle to make it something else? Obviously I'd need a new barrel, but I honestly don't know enough about it. Is rechambering as easy as having it rebarreled for something else, or is it a lot more involved than that?

If you rebarrel, you can choose from a multitude of chamberings. Ask the gunsmith you are considering to do the work and he should be able to give you guidence.

Nothing wrong with rebarreling to the 8x57 if you want. All new barrels are sized for the modern cartridge.

Let's move this down to the gunsmithing forum for proper placement.

Not to discourage you... but it would be a lot easier and cheaper to just load your own ammo, or find modern (european loaded) 8x57 ammo.

Is the a sporterized military 98 Mauser? If so, it should have the date of manufacture on the receiver ring. If it's after 1903, you have nothing to worry about -- it's bore for modern 8mm ammo (assuming it was originally chambered for 8x57). It could be rebarreled for just about anything up to .30-06 length, but there's not a thing wrong with a good 8mm.

Is the a sporterized military 98 Mauser? If so, it should have the date of manufacture on the receiver ring. If it's after 1903, you have nothing to worry about -- it's bore for modern 8mm ammo (assuming it was originally chambered for 8x57). It could be rebarreled for just about anything up to .30-06 length, but there's not a thing wrong with a good 8mm.
It is a sporterized military Mauser - it's a Mauser 98 Kar with what appears to be the original barrel - the taper is stair-stepped.

I didn't know about the 1903 date - I can't say for sure yet because I'll have to take off the scope base in order to fully see the date, but I would bet that it's post-1903 production.

Well, maybe I'll leave it in 8x57 - I have yet to fire it so I don't know what kind of grouping or accuracy I'm going to get out of it - I was just thinking that if I had a nice Krieger or Shilen barrel installed in .308, then most other things considered, accuracy would be a guarantee. :) Currently I don't reload but the ammo that I have that my Dad reloaded is:

150 gr Hornady bullet
47 gr of Hodgdon H335

His notation on the card in the box is 2650 fps. I think that's performance I could live with.

According to the Hodgdon manual I have, starting load for the 8x57 for H335 with a 150 gr bullet is 45 gr for 2507 fps, and max is 49 gr for 2744. Dad probably worked up the 47 gr load just to split the difference between starting and max and get good performance in the process.

there's not a thing wrong with a good 8mm

If you don't handload, and don't mind the limited availability of factory stuff, there are certainly no flies on this Euro favorite. I have never owned one personally, but some of my Swedish colleagues consider it a fine deer and moose (Swedish elk) round.

If the bore doesn't have too much life left, it could be rebored to 9X57, you'd need to form some cases from any number of available rounds. But performance would be somewhere between a .358 Winchester, and a .35 Whelen, and that is not a bad place to be.

[quote=trickg;329236I was just thinking that if I had a nice Krieger or Shilen barrel installed in .308, then most other things considered, accuracy would be a guarantee. :) Currently I don't reload but the ammo that I have that my Dad reloaded is:

150 gr Hornady bullet
47 gr of Hodgdon H335

His notation on the card in the box is 2650 fps. I think that's performance I could live with.

[/quote]

If it's a sporterized K98, you're good to go with .323" bullets.

A target-grade barrel certainly makes accuracy more likely -- but it's not necessarily a guarantee. While it's darned hard to make a rifle shoot well with a bad barrel, there are plenty of other factors involved.

That's a good, solid, middle-of-the-road load, knocking right at the level of the military 150 gr. .30-06 load with a slightly larger-diameter bullet. There are powders that will allow, with a solid rifle, 150-200 fps more than that with well-crafted reloads.

Although a bit pricey (what ammo isn't, these days?) Norma and RWS make some superb full-power loads that will give performance that equals or exceeds the .30-06. And, just in case you ever get into reloading, save the brass from these loads -- it's wonderful stuff!

Unless you have the money, you will be better off leaving it alone. In the day, surplus rifles were widely available and factory rifles were very limited and many, many mechanics did the work in the basements, cheap. How good? Long discussion.

#1). Go find a catalogue with dies and shell holders for reloading. Look up the shell holder for 8x57 and all the other rounds with the same size rim. You will find the same shell holder will work with anything from .22/250 to .35 Whelan. You can rebarrel to almost any of these.
#2). The round is 57mm long. You action was designed around this length. 57mm. You will NOT be able to go to the longest rounds like .300 H&H. You will not need action work with a similar round like 7x57mm. You should be able to "squeeze in" a round like 7.62x63mm better known as .30/'06...

From there--What suits your needs. .308? .243? .260? (Same rim diameter, slightly thicker, and slightly shorter.. 7.62 x 51mm NATO. ) It is an interesting exercise to "think this thru." But doing it costs money and you can buy one of many, many good rifles for less (with scope, often). Or shoot the 8mm. The original .318 bullet rounds are rare and if yours is anything made since 1925, the .323 will work fine and cheap. LUCK

Converting a M98 Mauser to .308 family of rounds may require some work on the action magazine rails to get it to feed properly since the .308 case has less body taper than the rounds that were originally chambered in the 98.

Based on the replies I have gotten here, it would seem that I would truly be better off leaving things alone with this rifle in terms of cartridge it handles. There are worse excuses one could use for buying a rifle in .308 :)

With that said, what kind of accuracy can I expect out of the original K98 barrel? Would it be foolish to have it re-barreled with another barrel for 8mm, or were the original barrels accurate enough?

Assuming the bore is in good shape, and that the barreled action is well-bedded in the stock, with good loads you may get accuracy anywhere from decent to absolutely outstanding. I once had a sporter converted by a talented amateur that not only looked great, but shot groups of under an inch at 100 yards with the very first handload I tried in it (one of many, many guns I never should have let get away!). I won't say yours will shoot that well, but it certainly might.

With my Dad's stuff, it's really hard to tell. It's obvious he shot this sporter, because I have his reloads for it, however, by far his favorite rifle was his Mauser 98 sporter in 25-06, which I also have. I can't tell by looking whether he did the sporter conversion on the 8x57 or not and I don't remember ever discussing that one with him. The 25-06 on the other hand was almost completely done by him, and it will hit a gnat's...backside at 100 yards. Or a prairie dog at 300. :)

Bah - I'll probably just leave it as it is and if I really feel the need for a .308, I guess I'll have to "settle" for something else purchased that way. ;)