- December 4, 2016 at 1:55 pm #31821goodyParticipant
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I guess this question falls into gunsmithing. For conversation sake when (what pressure) would a 98 mauser barrel burst with out receiver strength added to it. Then what would a typical new barrel of today fail with no receiver strength added to it. Too many days afield with no deer coming by gets me to wondering these thoughts. Also can aluminum receiver be used and if so at what pressures(I believe shotguns use it but that’s much lower pressure). Just wondering that’s all!
- December 4, 2016 at 4:02 pm #31828RegParticipant
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Generally and especially with modern barrels of good steel the barrel will take more than about any other component. I refer you to some of Ackleys test in his two volume set. In the case of the Arisaka action, he actually blew the barrel completely out of the receiver and down range a bit and the action and barrel both did not blow. He never said that I heard but assume the threads must have let go.
- December 4, 2016 at 5:48 pm #31838JPHollaParticipant
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As far as I know, all 98k mausers were made with “modern” alloy steel and the difference in the yield strength between the early nickel-steels and modern chrome-moly should not be of any concern. Aluminum can only be used for the receiver if it does not bear the load of the firing pressure. It has a maximum TENSILE strength below 80kpsi and yield strength about half that. It is also far too soft and would wear at the lugs, increasing headspace over time. Many alloys also fail from fatigue over time.
- December 5, 2016 at 12:46 am #31851HarterParticipant
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In the case of shotguns those with an alloy receiver lock the bolt into a barrel tang or multiple cam in lugs . Things like the AR platform also use a multiple lug cam locking bolt . I doubt that is correct terminology but rather a description.
- December 5, 2016 at 12:08 pm #31856GoodsteelKeymaster
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If you look at a bolt action Mauser rifle, there is only about 1/16″ (the distance from the face of the extractor claw to the face of the bolt) of brass protruding from the barrel into the receiver.
If you section a piece of brass, you will find that the bottom most 1/8″ of brass is solid, so the thin case wall is well supported by the barrel.
Then you figure that the threads on the barrel are about .600 long and 1.0″ around at the minor diameter of the threads.
Now, the receiver adds no strength to the barrel over this “tennon” area despite what people may think, theorize, or postulate on the web. A thread is a lousey way to contain pressure. The receiver can only help after the barrel has already expanded to fill those threads, and that only happens when the pressure was sufficient to compromise that 1″ solid steel ring surrounding the cartridge, and if that happens, the rifle is officially trash anyway and a tip of the hat to the receiver for not bursting as well when things went sideways.
It is not the receivers job to resist radial cartridge pressures (how could it? The barrel only enters the receiver less than 1/2 the cartridge length). The receivers job is to facilitate supporting all the doo dad’s that hold the cartridge, stuff the cartridge stab the primer, yank the cartridge out, eject it, etc etc etc.
It seems very obvious to me that anyone who takes a good honest look at the situation would come to the conclusion that the only part the receiver plays in containing pressure is the bolt lugs (to resist the rearward movement of the brass). Obviously, if the bolt were not there, the brass would be the projectile rather than the bullet. By arresting the rearward movement of the brass, the pressure will follow the path of least resistance, and that means blowing that plug of lead out the long skinny hole.
Dynamically speaking, the barrel expands slightly under the pressure when this happens (this is how Larry can read cartridge pressure by gluing a strain gauge over the area of greatest expansion) but the brunt of that expansion is over the forward portion of the body of the cartridge. It has everything working against it to press as hard in a rearward motion because the chamber is not a sphere. If it were a perfect sphere, then pressure would be the same in all directions, but it’s not, and it cannot press as hard in the rearward direction.
This is simple physics. A pop bottle is shaped and reinforced similarly to a cartridge case. If you apply compressed air till it bursts, where does it rupture? Always on the sides.
You would have to heavily reinforce the middle of the bottle in order to make it burst elsewhere.
This comes down to PSI. There’s simply greater square inches on the wall of an oblong chamber than there is on the ends.
That line of thought doesn’t even take into consideration the fact that one end of the cartridge is designed as a pressure relief which changes the equation even more in the same direction.
When all’s said and done, the barrel contains the pressure, the bolt makes sure the cartridge stays put and the bullet moves instead, and the receiver holds all this together.
Truthfully, the pressure on the receiver is between the threads and the bolt lugs, but then the weak link is those little lugs. Not the receiver ring.
With that understanding clearly established, I would put the original barrel at a bursting pressure of approximately 100K PSI and a modern barrel of only slightly more.
The point of rupture will start 2-5 inches in front of the receiver ring typically, and split slightly backwards and more forwards from that origination point (Do a google search for “burst rifle barrels” and you will see what I mean. Disregard pictures where the barrel split from the muzzle back as these are caused by a bore obstruction). If this rupture of a modern barrel is enough to exist in the first place, then the receiver ring is likely not going to stand much of a chance of arresting it (simply because of the thickness of the barrel in this area) while I could easily see the original Mauser barrel bursting slightly without damaging the receiver too badly.
That doesn’t change the fact that if a barrel of any vintage from the past 100 years bursts, something has gone terribly, terribly, wrong. To say that the reciever was at fault in such a situation would be akin to blaming the power of the engine, or the strength of the tree, for the damage to your totaled vehicle. How you direct the tools you have is what determines the outcome, and most firearm failure comes down to the operator using that firearm wrongly.
- December 5, 2016 at 4:29 pm #31861RegParticipant
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Goody’s question is actually a very good question as there is a bunch to be learned from it. Imagine the subject as a round ball and if you want to really see it you have to look all the way around it. In each way every response has been correct.
Every action out there has it’s own plus and minus’s and the 98 is no exception.
The action Mauser Model of 1898 was the end result of many actions developed through the years by Peter Paul Mauser and also one must consider he also looked at what else was out there at the time and learned from it and applied at least the thoughts of design to his crowning action.
The 98 was and still is a very good action but it has one aspect that few it seems know or consider,
After WW-1 the whole world was really not doing all that well or at least wasn’t doing as well financially as they may have thought they were. Germany was really on the dirty end of the stick. What was left of the Mauser works took stock of what they had and realized they had a gold mine in the 98 action.
It’ simplicity, it’s inherent strength and the ease by which it could be made all led to a idea that they sell the manufacturing rights all over the world and they did. Germany was not alone in this thought, we did the same thing with the 1903 Springfield design, Note, Tim, the Springfield book.
This led to the 98 action being made everywhere and in all conditions. Some of the workmanship and materials were of the best and some were unbelievably bad.
The one selling point from Mauser was that tolerances and material specs could be deviated from and the basic action design would still function and preform.
The actual strength of the action comes from not only the design but the fact it was actually designed to be made from varying quality materials from poor to excellent, generally low carbon steels and “wearability” would come from the fact it was designed to be case hardened rather than any other form of heat treating.
Anyone who has done much drilling and tapping on these actions quickly see this. The BRNO or “pickle barrel ” actions are hard and tough where many of the Spanish made actions are very soft and “gummy”. Some you actually have to go through a spot annealing process to mount a scope on them and some you can actually bind the tap in the soft and gummy steel.
I never kept track of how many barrels I worked on doing whatever was required but one thing sticks in the mind and that is this same quality variation also extended to the barrels. The barrels were not heat treated of course but not only did they vary in workability but also in tolerances. Seems like the general standard was to not let a thousandth or two get in the way. I never did see or hear of any Mauser barrel that failed ( burst ) due to manufacture or material.
Tim was right. If something ever goes wrong with a 98 or any other action for that matter, generally do not look at the action or barrel. Most likely you will find the problem was the loose nut behind the wheel.
- December 5, 2016 at 8:51 pm #31862goodyParticipant
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thanks everyone for your input. I get these questions from time to time and love learning so I ask!
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