FN Mauser Strength

Judging ALL similar make/model rifle actions by the capabilities of some can be dangerous.
I determined that the American Enfield (P17) was one of the stronger actions and had a 257Wby built on that action. Unfortunately, mine had been over-annealed during the drill and tapping process. After about 100 shots, it disintegrated and nearly killed me.
This is the hazard of ANY unknown 75-100 year old action that has seen no-one knows what abuse. After surviving that incident, I vowed to never own or shoot a rifle that is chambered for a round producing more pressure than it's original chambering. There are plenty of modern rifles that usually dollar out cheaper than "building" a surplus clunker.
 
I don't have better data. The data comes from places like mat web and I chose data for the same size of article. To get load you multiply psia by crossection, and these things were designed to carry load. It is just easier to discuss things in psia. Actual receivers and bolts are of different thicknesses and I am not going to take actual measurements and try to reverse engineer the design margins. Maybe someone out there with a FEM wants to do that, and I hope they share the information.
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I would like to see that data too.

However decades of both custom and factory m98 actioned rifles in 338 Win Mag and 458 Win Mag give me a pretty good idea that an M98 action is perfectly adequate for the task.

Obviously if the action is damaged somehow that is obviously not the case, but that is true of any action.

Jimro
 
Roy Weatherby used FN Mauser Actions when he first marketed his rifles,and Weatherby Magnum line of ammo. He had no problems with the action that I have heard of.
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So why did Weatherby develop the Mark V action? Weatherby was using post War, commercial made FN actions, not military actions that had gone through one or two rebuilds. I suspect Roy did not want to publish the number of FN actions that came back to his shop with cracked bolt lugs and developed the Mark V action because there was no commercial action on the market that could hold up to the constant pounding of Weatherby cartridges. Frank De Haas, in his book “Bolt Action Rifles” did not consider the post war FN #5 action suitable for belted magnums. Actually he sort of qualified it, it was suitable for low pressure factory 300 H&H and 375 H&H, but not for reloads. One customer of his, with 300 H&H reloads, cracked the rifle lugs.


Why would prestigious custom gunmakers use those Mauser actions if they were no good and unsafe?
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Prestigious assumes a lot of things. I am not going to assume the education level of any prestigious gunmaker, nor am I going to assume the guys warrant their work. You supply the action, they build it into a rifle, if you blow up one of their creations, it’s your problem, not theirs.

I have read a number of threads posted by “gunmakers” who have totally bought into the mystique of “old world craftsmanship” with old obsolete military actions. They don’t have a technical basis to support their emotional outpouring for old actions. They will however, take your money.

I doubt that any company is going to build a firearm designed for war to build a piece of junk. That would ruin their reputation and the country ordering would not accept them nor would they pay for them.
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FN built military actions that were perfectly suited to the cartridges for which they were chambered. I am certain FN does not warrant their old military action 70 years after manufacture and decades after being junked as obsolete military equipment. Nor do I expect will they recommend that their old military actions be in continuous use, or be used in belted magnum applications.

I am not going to do it, but I would be interested if anyone will take the time and effort to contact FN and ask them “Will you replace at no cost one of your WW2 era military actions if it breaks in use?”, “will you cover any medical costs if an injury results?”, and “are your military actions suitable for conversion to belted magnums?”

Here is contact information for

FN Herstal
Voie de Liege 33,
B-4040 Herstal,

Tel +32 4 240 8111.

Email: Info@fnherstal.com

Let me know their reply.
 
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I determined that the American Enfield (P17) was one of the stronger actions and had a 257Wby built on that action. Unfortunately, mine had been over-annealed during the drill and tapping process. After about 100 shots, it disintegrated and nearly killed me.
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This is interesting and I am glad you recovered. We are in agreement over your point about the questionable condition of old military surplus rifles and for not using them for cartridges that are overpressure and have more bolt thrust than for which they were designed.

But I would like to ask some questions, if you have the time. I have heard that many Eddystone receivers were brittle due to being overheated in the forge room. Are you sure it was due to annealing?

A bud of mine purchased a M1903A3 that had been converted to a drill rifle. I got to examine the receiver and it was mint looking, no evidence of a tiny tack weld that had been on the bottom. But, the receiver ring had been heated in the process and lost its heat treatment. He shot it with a new barrel and the headspace increased. He put on a new bolt to take up the headspace and after firing, the headspace increased more. If he had continued to shoot the thing he would have developed indications of excessive headspace. There is no guarantee his action would have failed gradually, but I think it is probably that would have been warning signs, such as difficult bolt lift or case head issues, before it would have blown. However, a failure due to a brittle receiver would be sudden. So, what did you see and how did it happen?
 
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Slamfire When did all these unfit Weatherby actions start blowing up? Sounds strange to me,If FN Weatherby actions had a problem I'm sure someone other than you would have heard of it.
 
Slamfire When did all these unfit Weatherby actions start blowing up? Sounds strange to me,If FN Weatherby actions had a problem I'm sure someone other than you would have heard of it.
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So why did Weatherby develop the Mark V action?
 
So why did Weatherby develop the Mark V action?
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Why to SELL of course!

Believe Wikipedia or not, this is a pretty good explanation.

Ever since Roy Weatherby began manufacturing rifles he had to rely on a third party to provide the actions for his rifles. Beginning in 1949 Weatherby began building his rifles around the FN Belgian Mauser action. In 1955 Schultz & Larson actions were added to the mix while adding the Mathieu left handed action to his rifle action line up. With the addition of the large capacity .378 Weatherby Magnum a new action type was warranted so the Brevex Magnum Mauser action was added. A little later the FN Sako Mauser actions were added to action types used by Weatherby to build his rifles.[2]

Roy Weatherby had been disappointed by the length of time that was taken discussing and negotiating before coming to an agreement with his European manufacturing partners. With five European companies supplying actions, the frequent trips made to Europe left him little time to run the day-to-day business operations in South Gate, California.[3]

Roy Weatherby had found the Mauser-type wanting due to the case head not being completely enclosed and supported within the breech. While these action types could easily withstand a high pressure of about 70,000 C.U.P, he felt that one which would have the capability of handling 200,000 C.U.P. would fare better with the Weatherby line of cartridges. He had been aware that many handloaders were overloading their cartridges seeking higher performance which was resulting in blown primers and ruptured caseheads. This in turn would lead to hot gases making their way through the bolt and into the shooter's face and eyes and causing injuries to his customers.[2]

Either way, the 338 Win Mag has a SAAMI MAP of 64k psi, well within the safe handling range of a mechanically sound M98 action. If the action isn't mechanically sound, then it shouldn't be used, with any cartridge.

Jimro
 
"But I would like to ask some questions, if you have the time. I have heard that many Eddystone receivers were brittle due to being overheated in the forge room. Are you sure it was due to annealing?"

It was not due to annealing. What the problem was, was the barrels were screwed on way too tight which cause some actions to crack. Other actions that were not crack would crack when the barrel was removed. The proper way to remove a barrel from an Eddystone Enfield is place the barrel in a lathe and make a relief cut where the barrel's edge meets the receiver. That relieves the stress and the barrel is removed in the normal manner. Not all the Eddystones had that problem but that's what needs to be done if you suspect and over tightened barrel on the gun.
I have an Eddystone I picked up cheap at a gun show because the barrel was badly corroded. It had been patrially customized with a decent Bishop stock, the ears removed and a nice receiver sight, This one has definitely been rebarreled and when I get the time it will go to Prescott Arizona to be rebored to .35 Whelen. I'll redo the stock while my regular gunsmith does a blue job and drills and taps for a scope. Should be a nice piece of work when it's finished.
Oh! And on that Enfield that blew up. You should be going after the gunsmith who did not know what he was doing. You have to spot anneal those receivers, not the whole damn thing. :mad:
Paul B.
 
Jimro, that was a very interesting link. I have read Stuart Ottenson's analysis of the Mark V action, in his book “The Bolt Action”, but I have never before read of the destructive testing conducted on the Mark V action. Based on the results, Weatherby’s action provides outstanding case support and is obviously very strong. I cannot imagine how any brass case could withstand 200K psia pressure. I don’t have a phase diagram but I would have thought cartridge brass would be a semi fluid at those pressures!

I handled a Brevex Mauser action and that action would be fine for a belted magnum. It was beatiful, I really wish I bought it. Standard M98 actions have to have the magazine opened up for some of those belted magnums and that removes material from the bottom receiver lug. The Brevex Mauser action was a over sized, massive action, and would be an excellent candidate for anything made on the belted magnum case. I see a complete rifle on the Brevex Mauser action going for $3,500 on Armslist. http://www.armslist.com/posts/82954...revex-magnum-mauser-custom-375-weatherby-mag-

But back to the standard Mauser and pressures. Actions are designed for a load. The barrel actually carries most of the load as the surface area of the cartridge in the chamber is much larger than the surface area on the bolt face. Maximum bolt face load is the area of the cartridge base times maximum chamber pressure, that gives a load. On top of that are safety factors, not to make the action stronger, but to take into account variations in steel, heat treatment, machining. So, lets say the safety factor on lugs is two, with a safety factor of two the designer hopes and prays given all the uncertainty in materials, processes, that the action will complete its service life with a load of one!

The next issue is service life, how many deflections was the bolt designed to before it cracks? This is the fatigue life. I think a really excellent explanation on fatigue life is to be found at this thread at post 12. http://castboolits.gunloads.com/showthread.php?150409-Ruger-om-44-convertible&highlight=convertible ColonelSanders is trying to explain why it is possible that a Ruger 44 Magnum could or would blow its top after 650 rounds. Basically, you stress something beyond its design limits, the fatique lifetime drops by orders of magnitude.

I have not seen a structural analysis of the standard M98 action, but I am very certain Paul Mauser was only designing his action for cartridges in the 8 mm Mauser class, not for belted magnums. A belted magnum has a larger case head and that will impart more bolt thrust and just how much, I calculated once, and I remember, it was significant. Now the commercial FN actions could have used a better grade of steel, alloy steels, and that would improve the load bearing of a FN commercial action, and improve on its fatique life. But, I don’t know. I have no doubt the military actions were made out of the cheapest steels that met the requirements of the military cartridge that the rifle was chambered in. Of course even with inferior materials a military action can withstand overstresses for a time, but no one should expect the thing to indefinitely handle overstresses.
 
Slamfire,

I don't disagree with you about increasing bolt thrust will decrease the action life. It is the same reason that aircraft are retired based on airframe hours, keep them flying too long and something really important will break when you don't want it to.

But there you have "failure points" where on an M98 in proper condition, will be the front locking lugs. The rear "safety lug" will still catch the bolt if the first two fail, a pretty good design factor in my opinion.

However, going from a 308 Win to a 300 Win Mag will only increase the bolt thrust 22%, from 10,279 ft/lbs to 12,640 ft/lbs. Since the 338 Win Mag has the largely the same external brass dimensions and max operating pressure as the 300 Win Mag it is a pretty safe bet that the bolt thrust increase over 308 Win is also in the 20-25% range.

If we assume that a 25% increase in bolt thrust will equal a 50% decrease in useable life of the action, then we can calculate about when we expect components to begin failing. So if we expect an m98 in 8x57 to fail at 20,000 rounds, we could expect the 338 Win Mag version to fail at 10,000 rounds. I don't know about you, but that would be several lifetimes worth of shooting a 338 Win Mag. Those aren't the actual numbers, just some picked randomly to illustrate the point.

Jimro
 
Slamfire, Roy developed the Mark 5 for:short throw, long length, and the prestige of having his own action. He became a true manufacturer and not just a custom shop when he developed his own action. And YES, it is very strong. It is also very easy to manufacture compared to a Mauser.
 
"If FN Weatherby actions had a problem I'm sure someone other than you would have heard of it."

They're ALL DEAD man and as we all know--Dead men tell no tales.
I always take a bucket and sponge when I go to the range, so I can get most of the blood and brains off the bench I want to use.
-----krinko
 
The rearward force on the bolt's lugs is the usual Pressure times Area, with the chamber pressure operating on the cross-sectional area of the inside of the cartridge case. The diameter of the case head is irrelevant.
 
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