Project: convert M48 Mauser to fire the 8x64 cartridge

[Colden]

I have a nice M48 mauser, and I found the 8mm cartridge, 8x57 JS--as sold by S&B--to be very appealing, and certainly similar to 30'06 in versatility.

What if someone converted this rifle to fire the more powerful 8x64 load?

It doesn't seem difficult, it's the same bullet diameter, although about 6 mm longer (case?) overall. Basically uses the exact same bullet. The chamber would need to be slightly elongated, but I think the magazine box is long enough!

I am aware of 8mm-06 Mausers, but I guess this is a little different. Factory ammo from S&B is available! Does this project sound possible? This rifle could be the king of all Yugo Mausers!

P.S. Of course there's also the 8x68, and so forth, but it may not fit. Did anyone actually think about doing this before? I'm not getting many hits on TFL or THR.

 

[Gabe]

One thing to watchout for is a Swiss machinegun round in 8mm. It looks just like the 8-06, but has a larger case and is more powerful. People have chambered this round by accident and damaged their rifle.

 

[Colden]

Not such a "hot" topic, huh?

 

[Snowdog]

Just my opinion, but I would imagine it would be less labor intensive to simply handload some real thumpers in 8x57 that approach the M48s pressure limits. From my understanding, there's plenty of case capacity in the old 8x57 to load up something that would damage your rifle; a longer case isn't needed for that.

Good luck and stay safe.

 

[Gewehr98]

Isn't the M48 (Yugo) Mauser an intermediate-length action?

Meaning it isn't the same length as the standard-length Gewehr 98, Kar 98, or Czech Brno VZ-24 actions. The M48/M48A was more suited for the 8x57 length than the .30-06, aka 7.62x64. Jim Keenan, where are you? Help me out here, I think getting this action to feed the .30-06 length family of cartridges may be asking for a lot of work, right?

 

[Jim K]

Hi, guys,

The M48 action is indeed shorter than the standard M1898 Mauser, though not by as much as sometimes said. The magazine is also shorter. The K.98k magazine has some 3-4 mm of "slop" ahead of the bullets, while that space is not there in the M48. The K.98k will almost accept .30 M2 ball, being only about 2mm short; the M48 won't come that close and more of the feed ramp would need to be cut away to accept .30-'06 rounds. I don't say you couldn't convert a M48 to take a cartridge of .30-'06 length, but it would be much easier to use a standard VZ24 or Model 98 action.

As for 8x64, there is not really a full millimeter difference in case length between the .30-'06 (7.62x63) and the 8x64. The .30 case length is nominally 2.494" (63.35mm), and the 8x64 is 2.508" (63.71mm), a difference of only about .014" or .36mm. The 8x64 has its shoulder farther forward and a shorter neck, so the feed ramps might need more work than on the .30 conversion.

So the job would not be as difficult as first appears, but I still think a normal length Mauser action would be far less trouble and expense to convert.

Jim

 

[Colden]

The reason for all of this nonsence is, of course, the hard to obtain full-power 8mm loads. The best I found is S&B--they have a "soft point cutted edge" 196gr load that is advertised to achieve almost 2600 fps in a 23.5" barrel.

http://www.sb-usa.com/rifle_pages/sba85703_spec.htm

Is there a better designed bullet, or faster, factory load out there that can be purchased in quantity easily? How much faster than 2600 fps could one push a ~200 grain bullet out of a Yugo M48 Mauser safely, without harming the rifle?

 

[Gewehr98]

Colden, just one question.

What are you trying to accomplish with the 8mm bullet? a 196gr 8mm softpoint, as offered by Sellier & Bellot at @2600fps, ain't nothing to sneeze at. I load 200gr Nosler Partitions pretty close to that velocity for my own sporterized 1917 Amberg Gew98 deer rifle, and it works just fine on Wisconsin whitetail, Colorado mule deer, and Wyoming elk. You going after something on the African Continent?

 

[Colden]

Just trying to maximize performance, and standardize on ammunition supply for my bolt-action centerfire rifle.

 

[Gewehr98]

Well, you *may* standardize on an ammo supply with that 8x64...

But it won't be as widely available, or popular as, the original 8x57 that Yugo M48 was built for. Then you have to add the effort and cost of reworking that action and reaming the barrel chamber for the longer round. You will have effectively limited yourself to that one round, and perhaps one supplier.

The performance of European-spec 8mm Mauser ammo is head and shoulders above the anemic stuff manufactured and sold here. But availability of 8x57 is still considerably better than the less-popular 8x64, and in a pinch you can still use the domestic fodder, albeit at a ballistic disadvantage. Or you can handload and recoup the difference in performance. If you go with the 8x64, that's a good handloading proposition. If you go with an 8mm-06 variant, it's a handloading-only proposition.

I seriously think you won't be underwhelmed by the energy and velocity of a decent 8mm Mauser load, say a 196gr softpoint, moving @2600fps. And if that Yugo M48's recoil is a bit sharp with that kind of ammo, you can always scale back and practice with either milsurp ball 8mm, or throttle back even further to the domestic 8mm stuff.

 

[Colden]

The earlier comments regarding the action size of the M48 got me almost convinced that a 8x64 or 8-06 rounds wouldn't fit. I checked, and the magazine indeed only has a few millimeters to spare. Maybe 3-5, but evidently not enough.

So, scratch that, I will instead have to standardize on the 8x57 JS ammunition. Does anyone know a source for Norma? I heard it may be hotter or better suited for hunting than S&B. I can't seem to find any information to compare Norma to the 196gr at 2600fps S&B ammo.

 

[ojibweindian]

Here's Norma's home page: http://www.norma.cc/sida/eng/index.html

The ballistics link will take you to an on line ballistics program that has data concerning their 8x57 loads.

 

[Jim K]

I got some 8x57 S&B FMJ a while back and it is German GI specs, which means it is sure nothing to stand in front of.

The 8x57 can be handloaded to VERY hot in a good Mauser rifle, and the Remington 700 Classic is now available in 8mm if anyone wants to load up some real screamers that should only be used in an enclosed head action.

BTW, has anyone checked the price and availability of 8x64 factory loads? S&B is around $30 a box of 20, and they are the only source I can find, as Norma does not load it any more.

Jim

 

[Colden]

Well, what do you know! Norma's 8x57JS is less than 2600 fps as well! 2526, actually, while S&B is 2580-2590! Same weight, 196gr. Who was saying that Norma loads 8mm Mauser hotter?

Yeah, 700 is indeed available in 8mm! That's cool, I want this caliber to be produced locally in more powerful loads. Let them call it .323 Remington, I don't care, as long as it's loaded at 2600-2700 and around 200 grains.

Purely theoretically, given the strong Mauser action of the M48, how much increase in ~200gr bullet velocity over 2600 fps can be obtained, before the pressure is unsafe or damaging to the rifle? I want to know this simply to judge what I am missing by buying factory S&B soft-points.

 

[only1asterisk]

I think after you run some full power loads through your rifle you'll find that a better use for your money will be a new stock! I have a little experience with the 8x57. It is my opinion that 200 grain partition at a little over 2500 fps is plenty for North American game from mouse to moose. If you are using the sights on your rifle, you don't need any extra velocity. Your range will be limited to 250 yards or so anyway.

If you are planing a total remodel (stock, scope, bolt handle, safety, etc) then it makes more sense, but I like the 8x86s loaded long and that will not fit into the action well. If you want something unique, consider the 8x60s. RWS makes great brass, and it is designed to work in the action with no alteration.

Good luck with your project, let us know what shakes out.


David

 

[ojibweindian]

Purely theoretically, given the strong Mauser action of the M48, how much increase in ~200gr bullet velocity over 2600 fps can be obtained, before the pressure is unsafe or damaging to the rifle? I want to know this simply to judge what I am missing by buying factory S&B soft-points.

A ~200gr 8mm bullet with a MV of 2600fps, +/- a few fps, is nothing to sneeze at. Within reasonable ranges, it will kill anything you would likely come across. Why take a perfectly good rifle like a Mauser, or any other rifle, and subject it to pressures that will not significantly improve downrange performance?

If you want a flatter shooting load, roll your own cartridges. A 170gr bullet at roughly 2800fps would be great to roughly 250yds; no holdover.

 

[Cosmoline]

Rolling your own would be a LOT less trouble. It's pretty easy, and 8x57 dies are easy to find. There's a surprisingly good selection of 8mm bullets, as well. The only caution is that some of the .323" bullets are actually designed for the 8mm Rem Magnum and may not work as well at lower speeds. That said I found that 8mm 200 and 220 grain Barnes X bullets were very good out of my Yugo and CZ. The Barnes 220 grain solids were the most accurate of all.