I have an old mauser 98. It is an obendorf 1917 rifle that has been much sporterized. It is chambered for the 6.5x55 Sweede. It shoots well particularly with loads that are at the top of the book loads. The loading manuals say these loads are for modern rifles only. Do I risk damaging this old war horse? My understanding was that the 98 action was one of the strongest out there. Still in 1917 Germany may have been in a bind for getting good steel. What do you think? "D"

By the way it is chambered for the 6.5x55.

The M98 action was tested up to 100000PSI back in the old days...Please read Richard D Laws book " Backbone of the wehrmacht"...Lots of good tech-info.

Hi Jens
100 000 psi !!! are you sure about that? it sounds very high . many of calibers at that time were made för working pressure of 50 000 psi or less and it is more than double of their working pressure!!!
regards
yes

The brass case will fail long before the rifle action. After all, which do you think is weaker, .02" of brass or a quarter inch of steel? If your cases aren't leaking at the primer or expanding to the point that they are unusable for more than a few reloadings, then your rifle action strength is not an issue.

quote:

Originally posted by Stonecreek:
The brass case will fail long before the rifle action. After all, which do you think is weaker, .02" of brass or a quarter inch of steel? If your cases aren't leaking at the primer or expanding to the point that they are unusable for more than a few reloadings, then your rifle action strength is not an issue.

Unless you have Mauser with a receiver hardness of Rockwell B-80.

I have overloaded lots of Mausers, and I have been unable to dent the bolt lugs into the receivers.




But in taking the barrel off ~60 different 98 Mausers, I have found some freshly surplussed Mausers with dented receivers.

Maybe it was not a load work up, but a barrel full of mud. I don't know, but the Turkish military did it somehow [maybe while shooting at Churchill in WWI].

I like to build a fixture and lap the lugs against the receiver so there is more area, and denting would be even harder to do.

As AssClown used to say, "~Receiver surface hardness has nothing to do with strength, it is about corrosion resistance."

quote:

Originally posted by ireload2:

quote:

Originally posted by Stonecreek:
The brass case will fail long before the rifle action. After all, which do you think is weaker, .02" of brass or a quarter inch of steel? If your cases aren't leaking at the primer or expanding to the point that they are unusable for more than a few reloadings, then your rifle action strength is not an issue.

Unless you have Mauser with a receiver hardness of Rockwell B-80.

I've seen a lot of failed brass cases where the action didn't fail, but I've never seen an action that failed and the case didn't fail first.

Of course the problem is that a gross overload could cause an action failure without pre-warning, but assuming that the shooter is reasonably linear in his load development it would be a rare circumstance that unacceptable brass "wear" wouldn't show up long before the action was in danger of failure, no matter the metallurgy of the steel (provided that a previous incipient failure did not exist).

Basicaly the M98 is a strong reciever, but the lack of casehead support caused by the controled feeding, causes it to fail even before a PF action showes heavy boltlift.

Cause: When the casehead lets go, the actual preasurearea on the boltface is increased by 200-300%.

Result: You gets Major lugsetback, or even total failure.

Our tests showed that CRF actions in standardcalibers failed abour 80.000psi, where several PF actions handled up to 135.000Psi

quote:

I've seen a lot of failed brass cases where the action didn't fail, but I've never seen an action that failed and the case didn't fail first.

You need to look around a little bit more.
Have you ever seen a Krag bolt with no locking lug?
Want to check out my 1898/09 Argentine Mauser with .030 excess headspace? Complete with matching serial numbers on the barrel and receiver.

The yugos made a safety breach for their mausers so it it can be reproduced with the extra work that it takes to make an extracter cut in the barrel.

Rad

quote:

Originally posted by HerrMesser:
The yugos made a safety breach for their mausers so it it can be reproduced with the extra work that it takes to make an extracter cut in the barrel.

Rad

That and removing the cartridge guides at the front of the bolt on either side of the extractor slot.

Catestrophic failure was not exactly what I was worried about. It is the slow bending or distortion of the metal that I am concerned with. I am sure I am not the first person to load these old mouse guns up to at least warm. Some of you smiths I am sure you have seen some shot at pressures I am not interested in going for. See any warped actions?

quote:

You need to look around a little bit more.
Have you ever seen a Krag bolt with no locking lug?
Want to check out my 1898/09 Argentine Mauser with .030 excess headspace? Complete with matching serial numbers on the barrel and receiver.

Are you saying that with the failed Krag that the brass was intact and reusable?

As to your Argentine, I don't consider an action which is intact and still containing pressure as having failed. It may be worn or stretched, and someday may indeed "fail", but if and when it does, I can assure you that the case will also fail; and by definition, it will have failed first.

Rifle action strength and failures are not simple subjects. You should get Vol II of P. O. Ackley's Handbook where he devotes two chapters to those subjects. Some of his recorded test results will surprise you.

Ray

quote:

Originally posted by Stonecreek:

quote:

You need to look around a little bit more.
Have you ever seen a Krag bolt with no locking lug?
Want to check out my 1898/09 Argentine Mauser with .030 excess headspace? Complete with matching serial numbers on the barrel and receiver.

Are you saying that with the failed Krag that the brass was intact and reusable?

As to your Argentine, I don't consider an action which is intact and still containing pressure as having failed. It may be worn or stretched, and someday may indeed "fail", but if and when it does, I can assure you that the case will also fail; and by definition, it will have failed first.

The Argentine is definitely failed regardless of your definition. Factory ammo shoots in it but does not separate. But that hardly makes it safe. Don't tell me you would shoot it and consider it normal as is.

The Krag bolt suffered a brittle failure.
It broke like a piece of glass. No case failure. Several months back there was a FN 98 bolt here that failed by brittle failure. No fault of the load or the case.

quote:

The Argentine is definitely failed regardless of your definition. Factory ammo shoots in it but does not separate. But that hardly makes it safe. Don't tell me you would shoot it and consider it normal as is.

Okay, the Argentine "failed" under some unspecified definition that you subscribe to. It has not "failed" under the definition that I have used. Now we're arguing semantics, not firearms.

A lot of chambers are unnecessarily longer than the ammunition you might put in them. This in and of itself means little. Unless you have some evidence that the chamber has grown longer due to set back of the lugs, then it does not necessarily follow that there is a "failure", even by your definition, taking place.

For the sake of argument, let us assume that the chamber on the Argentine has lengthened due to lug set back. Without knowing what kind of loads caused the set back, it is again not possible to say that the action is "failing". After all, the set back could have been cause by a single greatly excessive load that destroyed the brass case and required extraordinary measures to open the action for its removal. If that were the case, then clearly the brass case would have failed ("blown up"), but the action, although damaged to some degree, would have remained intact, i.e., not "failed".

Again, my point is that it is difficult, if not impossible, to have a set of circumstances in which the relatively fragile brass case does not fail, or begin to fail, well before the steel of the action will give up in catastrophic failure. Certainly steel of an improper metallugy or hardness can and will "wear", i.e., deform, even with loads generating pressures less that that which will cause the brass case to fail.

I have a 1918 Oberndorf action.
My intention is to run it as hot as a Mauser brass case head will bear, like 65kpsi in a .270 or 65kpsi in a 6.5x55.

Should the bolt lugs make dents in the receiver [very small chance], then I will either lap the lugs and set the barrel back or get a new receiver. In either case, there is not danger to me or anyone else.

quote:

there is not danger to me or anyone else.

You are one bad case away from making a mess of your face.

quote:

For the sake of argument,

Ok when a rifle is dangerous to continue firing I consider it failed regardless of your semantics.

FWIW....in the engineering world the lug setback would be referred to as a compression failure.

This is nowhere near the type of "failure" one might experience after a ruptured case as that could be catastrophic!

However it would be considered a failure and in need of design changes. Design changes may include geometry, type of steel or heat treat specified or all of these things.

Not that this is right or wrong but if it was my action, I'd not consider using 65,000 PSI loads in a 1917 Mauser until it was sent to a reputable heat treater for hardening as done by Burgess etc.

Whats your face worth ?. A 1918 or 17 Mauser ?.

They are very strong actions . How ever 65K PSI is asking a little much of a battle weapon which has seen years of abuse care neglect ?. One never knows looks are deceiving . Take Bill Clinton ! Please and his other half !.

They make proof barrels for testing loads !.

I agree with VapoDog !.

Shoot Straight Know Your Target . ...

All of my Mauser 98's have been strong enough to have no lug setback, no pieces flying off them with proper reloads. Isn't that all that's required?

I buy guns, take them apart, try to understand the design, clean them, lubricate, reassemble, overload with handloads, write up a report, throw what is left in storage. I have a few hundred guns of over 60 cartridges in storage. This is my hobby. I am not getting paid.* I can now just look at a gun and cartridge and tell if the brass or the firearm will fail first in an overload work up.

My favorite guns to overload are Ruger #1s and old surplus 98 Mausers.

The 1903 Turkish Mausers were made between 1903 and 1905 at Oberndorf. These actions are shorter [than the subject 1917 action] and intended for 7.65x55 and rebarrelled and restocked in 1938 by the Turks for 7.92x57. These were 4/$100 delivered 5 years ago. There are plenty around. I have overloaded the 8mm cartridge in them until the primer falls out and I have to jump on the bolt handle like a pogo stick to get the case out. Sometimes the bolt handle needs to be struck with a big hammer 100 times. Sometimes the barrel needs to be taken off. I can't get the lugs to set back, but if I take the barrel off 50 of these old rifles and look at the receiver, 6% are dented from the lugs getting set back. I don't know WHAT those Turks were doing. One theory is mud in the barrel before 1938.

One experiment I have not done yet is to anneal a 98 Mauser receiver and bolt body, and then overload and measure headspace. Mauser case heads fail at ~73,000 psi and it would be interesting to see if the Mauser design is stronger than the brass without any heat treat. My guess is that it will set back unless the lugs are lapped first for more contact area.


* I do charge a fee for designing power electronics, and I have always tried to blow them up with overloads to test the design. I was not the only one to think of this. These days, Highly Accelerated Stress Test (HAST) has become popular and formalized.

tnekkcc,
I have read second hand accounts that the Turks reheat treated their receivers when they went from the 7.65 to the 8X57. You would certainly hope so in the case of the M93 models that were converted to 8MM.
The one Turk (marked ATF 1954) I have is a Czech receiver. It has negative headspace, that is it will not accept a go gauge but will chamber loaded ammunition. Every part is mismatched. Most of the other parts look like GEW 98 parts. They were just Frankensteined out of loose parts like a complete tear down and reassembly.

I would be curious to know what percent overload do you use. Some of case head failures I have had were in Lee-Enfields and did nothing to the rifle because they were not over pressure loads just head separations due the large chamber and Lee-Enfield design. A .22 Hornet is easy to expand without damage to the fire arm.
The only Mauser I have personally blown a primer in was an M91 and it was not damaged.

You might try testing cheap shotguns for a break from the monotony. I am sure it would be much more spectacular.

I overload until the brass fails or the gun fails.

If I just jump to some overload in the first step and the gun blows up, I "don't learn much".

There was a grumpy old ME prof who worked on missiles that blew up on the launch pad. He said you don't learn much when that happens

I can jump to a 250% powder charge in 25acp, but I can't jump anywhere in 270.

The 303 Brit Enfield is a special case.
The rimmed case is strong.
The headspace and ammo SAAMI registered tolerances are the loosest I know about.
The action is strong, but springy.
I did not believe, at first, that the action was springy when I read that in Ackley. But getting out the calculator and calipers, the bolt body walls are thin and the lug is in the rear. Just the compression of the bolt body should be enough of Hooke's Law to eventually separate case heads if the brass can stretch elasticly for .002".

quote:

Ackley II 1966 page 13:
"The locking lugs themselves did not give way.
The whole action appeared to have plenty of strength except for this
one characteristic,
which allows too much spring in the bolt and receiver."

"Speer 13" 1998 page 333:
"Lee Enfield rifles were make id dizzying number of variations but all
share one common feature. The bolt locks at the rear causing the action
to be somewhat springy. This limits the 303 to rather modest pressures
and case life is usually short. ... the Enfield Pattern 14, uses a
Mauser-type lock-up. It is much stronger than any Lee-Enfield.. The P14
Enfield with its front locking lugs gives much longer case life."

SAAMI is .054 to .064 cartridges and .064 to .071" chamber.

No 4 bolthead sizes:
0 - .629 to .625 in.
1 - .625 to .630 in.
2 - .630 to .635 in.
3 - .635 to .640 in.

I am finding brass from .056" to .063" on the thick side of the rim.

I called all over in the US and Canada and I cannot find any more No 3 bolt heads.

I got some surplus heads, but they do not clock the threads, and require work on both ends.

I made this lathe and soldering fixture for 303 bolt heads. With it I can Silver Solder a shim on the bolt face. Soldering is easy. Cutting a good firing pin hole is hard.




Some other old guy in Florida tells me he has been soldering shims on the bolt face for some time to headpace old No 1 303s.

I had the same results loading for a MAS 36/51.
Loads that you would think normal gave sticky extraction. The bolt and receiver in the MAS are massive compared to the Lee-Enfield.
The worst feature of the Lee-Enfield / .303 combination is the .460 camber diameter at the rear of the chamber and the .450 case head diameter. There is just too much radial stretching going on added to the springy action. .444 Marlin brass makes good .303 cases but are time consuming to make.

And the MAS was the last military bolt rifle designed


Mine is minty and unfired, for symbolic reasons.

quote:

Mine is minty and unfired, for symbolic reasons.

Lol, that is a dig.

My 36/51 was the grenade launching version and had never been fired much less launched a grenade in anger. The sights were excellent but it came and went before boxer primed brass was available. I swaged Norma 7.5X55 down to shoot it but got tired of that.