Yugo M48 Mauser 300WSM

[SixFive]

Guys I need some advice or knowledge. I have built several .300WSM Mausers on 98 actions over the years with no issues. I have two Mauser actions left in my junk box I am going to build on. One is a 1950s Spanish 98 action and one is a YUGO M48 action.

I know there has been years of debate on the hardness of the Spanish actions so I will build it in .308 and not worry about it. I however have not found these actions to be soft, in fact lapping in the lugs is a chore due to the hardness!

I want another .300WSM so I was thinking of using the Yugo M48 action for this. Does anyone know of a reason the Yugo M48 post war action would not be strong enough? There seems to be nothing out on the Internet about anyone else doing it. Thanks for any advice!

MAX .308 pressure is - 62,000 psi
MAX .300 WSM pressure is - 63,817

I have no worries chambering pretty much any Mauser in .308 and I see the pressure are similar so am I worried about nothing? I am aware there are other consideration than pressure like bolt thrust.

Just a note I handload everything and I am usually in the middle, I am not a HOT loader.

I did find one thing on the Internet if it is to be believed -

Zastava M48 Mauser: Milsurp Gem | Breach Bang Clear

The Yugoslavian M48 Mauser is hard to beat if you want a tough, economically priced, high-quality bolt action - or if MILSURP is your thing!

www.breachbangclear.com

"The action is so robust that, when produced with proper materials, it can handle 100,000 pounds of pressure and still remain operational. Of course, it couldn’t withstand such pressures for long, and the standard World War II 8mm Mauser load exerted about 45,000 psi."

 

[Ggmac]

hardness is just as bad a being soft , if not more so . Soft lugs give , glass hard don’t , they shatter just like some early 1903s . I no longer trust any spanish military , I have pieces of a few here that were shooting FACTORY 150 gr Remington and it blew . The bolt was blown up andalmost out the now topless receiver.
You may not reload hot BUT when you are no longer its caretaker, what will the next guy do ?

 

[Sniperhandle]

The YUGO M48 action is a very good action, The breech face is different than a standard 98 and has a So called "Safety breech" and an extractor cut, This action may be harder to get it to feed. The only short mag I have done is 6.5 PRC on mausers but I have not done one on a Yugo, I have done a couple in 308 and they are perfect for it.

 

[Sniperhandle]

And now that I think about it more, I would not do a Short magnum on one of these actions as the safety breech would be very thin. I have a pic of a barrel I did on a MAUSER 98, That I converted to 7.62x54R, SO It is a little different and in the pic I had not made the extractor cut yet, But you can see the safety breech which is machined to fit the corresponding hole in the C-ring, SO the safety breech on a short mag would be pretty thin. The safety breech would be 0.085 smaller in diameter.

 

[tobnpr]

in fact lapping in the lugs is a chore due to the hardness!

Keep in mind that case hardening, while it varies- is generally .002-.008 thick, and inspection before rebarreling should show only light "wear polishing" on the receiver lug abutments. Any more than that (.002) and the receiver should be rejected (or re-worked, and then re-hardened). Lapping lugs needs to be minimal if at all, if the case hardening is worn through setback is rapid and becomes potentially dangerous (all of this is from Kuhnhausen's book, that any smith working on Mausers should have).

I've not worked on a Yugo- nor examined the barrel breech in detail, but it appears to me to be "optional". Other countries refused to adopt the "safety breech" due to increased cost and complications.
One can easily eliminate the counterbore on an M700. Dangerous? Hell no, no more than any other flat-breeched rifle which are far more common. The casehead is plenty thick in that area without need for additional external support.

Sounds like an interesting project to me (I'm getting ready to do a Mosin-Nagant in .300 WSM, also one of my fave cartridges)- the M48's never saw combat and are typically pristine. The WSM's are finicky feeders, but I'd lose the safety breech, mill out the receiver, open the boltface and give it a go.

 

[Ggmac]

And now that I think about it more, I would not do a Short magnum on one of these actions as the safety breech would be very thin. I have a pic of a barrel I did on a MAUSER 98, That I converted to 7.62x54R, SO It is a little different and in the pic I had not made the extractor cut yet, But you can see the safety breech which is machined to fit the corresponding hole in the C-ring, SO the safety breech on a short mag would be pretty thin. The safety breech would be 0.085 smaller in diameter.

You know that can be fitted like any other mauser with no feeding or safety issues even though the bolt nose is different. There is a reason it wasnt used by the majority of mausers . The case protrusion on a std 98 is .110 , very little compared to remington or savage .

 

[Ggmac]

Keep in mind that case hardening, while it varies- is generally .002-.008 thick, and inspection before rebarreling should show only light "wear polishing" on the receiver lug abutments. Any more than that (.002) and the receiver should be rejected (or re-worked, and then re-hardened). Lapping lugs needs to be minimal if at all, if the case hardening is worn through setback is rapid and becomes potentially dangerous (all of this is from Kuhnhausen's book, that any smith working on Mausers should have).

I've not worked on a Yugo- nor examined the barrel breech in detail, but it appears to me to be "optional". Other countries refused to adopt the "safety breech" due to increased cost and complications.
One can easily eliminate the counterbore on an M700. Dangerous? Hell no, no more than any other flat-breeched rifle which are far more common. The casehead is plenty thick in that area without need for additional external support.

Sounds like an interesting project to me (I'm getting ready to do a Mosin-Nagant in .300 WSM, also one of my fave cartridges)- the M48's never saw combat and are typically pristine. The WSM's are finicky feeders, but I'd lose the safety breech, mill out the receiver, open the boltface and give it a go.

You type faster than I do !

 

[Sniperhandle]

You know that can be fitted like any other mauser with no feeding or safety issues even though the bolt nose is different. There is a reason it wasnt used by the majority of mausers . The case protrusion on a std 98 is .110 , very little compared to remington or savage .

That may be, But the bolt nose has had the rim holding nubs shortened a lot on the M48, So the bolts have differences between the M48 and the M98. When I did my .308's on M48 Actions I did them the way they were designed.

Tobnpr

I have done the Mosin in 6.5 Prc too. Sounds like a fun project. For the Heavier calibers I like to use WW2 era Mosin actions as i feel by then the heat treating and steels were better.

 

[JSH]

FYI, the screw spacing is shorter than a 98. I must have been the only one in this galaxy that did not know that. I found stocks to be few and far between for what I was after, varmint type.

 

[Sniperhandle]

FYI, the screw spacing is shorter than a 98. I must have been the only one in this galaxy that did not know that. I found stocks to be few and far between for what I was after, varmint type.

Yes, Everything is shorter on the M48, Mounts, Stocks, Bolts, Action, T-guard etc. That's why they make such a nice 308, 243 etc.

 

[SixFive]

I think I am going to just do the M48 in .308 and skip the 300wsm. Practically speaking I only hunt deer to 300 yards on my property and I already have an abundance of different magnums if I so choose to hunt them. Plus I already have a 300wsm on a German 98 that works fine, I figure why push the envelope. After reading the comments here I just am not comfortable with building the 300wsm on the action, a little voice in my head keeps nagging me about it.

 

[DGP4]

I'd do it in a 7-08. I have a Swedish M96 Mauser in .308 and that will be the caliber I re-barrel it in.

 

[SixFive]

I'd do it in a 7-08. I have a Swedish M96 Mauser in .308 and that will be the caliber I re-barrel it in.

I do not want to tool up for another caliber if I do not have to.

I have everything to do the following -
6.5-284
6.5 Creedmoor
.308
6.5x55se

It gets expensive, chamber reamers, head space gauges, loading dies, and then components.....

I ordered a 27" barrel blank 6.5mm 1:8twist today, just to have a spare, maybe I will do it in one of the 6.5x55 swede is -

Maximum pressure (SAAMI)

351.6 MPa (51,000 psi)

Either action should handle that with no issue. But even 6/5-284 Norma is -
Maximum Average Pressure (MAP)* = 58,000 psi Instrumental Velocity: 130-gr @ 2,900 fps

That is MAX, it is also my absolute go to round for hunting. Decisions...

 

[Sniperhandle]

6.5x55 swede is what I do do too!

Just remember to make sure it fits the bolt face.

6.5x55 Lapua brass is 0.480 and Remington is 0.473

 

[SixFive]

I ended up building the Yugo M48 in 6.5-284 Norma, sure turned out sweet. 27" barrel, Boyds Walnut stock. I worked the stock trigger to 2lbs breaks like a glass rod. Had to open the feed rails just a tiny little bit and it feeds like a charm.

This old Yugo had been opened to a Magnum bolt face many years ago, I had to rebuild it to a standard bolt face. Lots of work actually...

 

[jackieschmidt]

Keep in mind that case hardening, while it varies- is generally .002-.008 thick, and inspection before rebarreling should show only light "wear polishing" on the receiver lug abutments. Any more than that (.002) and the receiver should be rejected (or re-worked, and then re-hardened). Lapping lugs needs to be minimal if at all, if the case hardening is worn through setback is rapid and becomes potentially dangerous (all of this is from Kuhnhausen's book, that any smith working on Mausers should have).

I've not worked on a Yugo- nor examined the barrel breech in detail, but it appears to me to be "optional". Other countries refused to adopt the "safety breech" due to increased cost and complications.
One can easily eliminate the counterbore on an M700. Dangerous? Hell no, no more than any other flat-breeched rifle which are far more common. The casehead is plenty thick in that area without need for additional external support.

Sounds like an interesting project to me (I'm getting ready to do a Mosin-Nagant in .300 WSM, also one of my fave cartridges)- the M48's never saw combat and are typically pristine. The WSM's are finicky feeders, but I'd lose the safety breech, mill out the receiver, open the boltface and give it a go.

Good points.
Case hardening does little or nothing to increase the actual tensil and yield strength of the parent material. It is used to keep moving parts from getting degraded in less than pristine operating conditions, such as a combat soldier would face.

The vast majority of military actions were not manufactured from alloy steel that we have become accustomed too. Most are carbon steel with a few proprietary elements added to enhance mechanical properties while keeping material and tooling cost at a minimum. You simply did not need an action that would contain 65,000 psi on a consistent basis when the most it would ever see is around 48,000.

The only slight dissagreement I would have with your statement concerning the Remington 700 is the counterbore was never intent on enhance the support of the case head. Make Walker’s “three rings of steel” were incorporated o contain gas and flying parts in the event of a case head failure.

I have seen one subjected to an overload that literally welded the case head inside the bolt counterbore. The barrel had to be removed to finally get things freed up. It was all pretty much scrap but the shooter suffered no more ills than being a little embarrassed.

But you are correct.about the flat back barrel tenon. You will loose a few threads, but properly fitted, I doubt it would be of any consequence.

 

[SixFive]

The Yugo M48 is not your typical military grade Mauser, they were built in the 1950s-1960s and were FORGED. Should be as strong as any commercial action of that era was. I read they have been tested out to 100,000PSI so I have no worries about the strength.

Also there was NO back tenon or anything else different about the barrel or bolt, the bolt has a standard 98 configuration as was the original take off barrel. Besides being a bit shorter than a standard 98 everything else is the same, on this one at least. I was able to use a 98 Mauser extractor, trigger, safety, cocking piece, and bolt shroud, without any modification (I had long ago lost most of the original parts). The firing pin is SHORTER but that's about it....

The big job on this one was rebuilding the bolt face from magnum back to a standard bolt face. I didn't want to "solder" a ring and machine it, I turned the bolt face flat in my lathe, welded on a new 01 tool steel piece of round and machined back to original Mauser specs for the standard bolt face. I never got the front lugs hot enough that I was not able to touch them, welded one spot at a time, let it cool, over and over until it was done. Everything works fine and the bolt is spec now.

 

[shortgrass]

All of the European made Mausers of that era (1891 thru 1898) started out as a red hot billet under a drop hammer, and forged into their basic shape and then machined. That's all forging is , hammering a piece into rough, basic shape. Makes for less machining and lower overall cost in the end. The Yugo 24/47 is a darned tough Mauser '98 style action. I have little experience with the model 48 as it uses stamped bottom metal and doesn't have the overall fit and finish of the 24.

 

[SixFive]

All of the European made Mausers of that era (1891 thru 1898) started out as a red hot billet under a drop hammer, and forged into their basic shape and then machined. That's all forging is , hammering a piece into rough, basic shape. Makes for less machining and lower overall cost in the end. The Yugo 24/47 is a darned tough Mauser '98 style action. I have little experience with the model 48 as it uses stamped bottom metal and doesn't have the overall fit and finish of the 24.

The Yugo M48 was not of that era though, it was made starting in the 1950s post war. Not sure if that means anything but I would expect production quality was better? Maybe? Outside of war. I do not pretend to know but I have not in all my searching found anything about Yugo M48 actions being anything but strong. Hopefully that is accurate, I shall find out

 

[shortgrass]

Oh! The 48 is tough enough, it just lacks the fit and finish of the 24. Same steel. same manufacturing process, made in the same factory using much of the same tooling, just not as 'nice' as previous models.