Home Forums Hunting & Shooting Ask The Gunwriters Receiver strength - metal or diameter

Ken and others,
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<br>Had some free time yesterday and was flipping through some of my Mauser rifle books. I noted the usual, many warnings against building a rifle chambered in a magnum or other high pressure cartridge on the small ring 96 style receiver. After comparing the front ring diameter of the 96 (1.3�) and 98 (1.4�), as well as that of a Remington 700 (1.360�), I had a few questions.
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<br>Is it strictly the metal quality that limits the strength of the 96 style receivers? I do not doubt that chambering and firing a high pressure cartridge in a 96 based rifle would be detrimental to the health of the rifle, and most likely the shooter. However, I find it hard to believe that the extra .060�-.100� (actually half that amount per side) would enable an action to withstand an additional 10,000-20,000 PSI or more on a continual basis.
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<br>If the metal quality is the only strength limiting factor, would a 96 replica made with better/stronger metals under better controlled conditions be suitable for higher pressure cartridges?
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<br>What is the smallest ring/receiver diameter considered �safe� for high pressure cartridges? Or, does that diameter have little to do with the strength of the action compared to the quality of the metal used?
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<br>Any additional thought on the matter would be appreciated.
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<br>Brandon
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You've just stuck an exploratory toe into a very deep and turbulent pool. The strength of actions -- more specifically their receiver rings -- is not nearly as simple a matter as our druthers tell us it should be.
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<br>For instance -- if I understand it correctly, the weakest of the three things working together to contain high chamber pressures (case, chamber, and receiver-bolt lock-up) is the receiver. It depends heavily on the head of the case to keep the rising gas pressure contained, and it goes to bits and pieces surprisingly easily if the case head gives way and lets wild gas get loose. I'm told (don't know whether it's true) that pressures as low as 10,000 lb/sq in. are enough to burst a receiver if the case lets wild gas loose to rampage through the action.
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<br>I find this scary enough to make me VERY careful about keeping gas pressure well contained at levels well below "maximum," whatever that is or how it's determined.

ken,
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<br>given what you have just said (the weakest point in a receiver being the case head), would there be any validity to weatherby's receiver strength claims (in terms of completely encasing the case head in 'three-rings-of-steel')?
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<br>many thanks for your thoughts.
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<br>te

Tom, I thought I said that the weakest component is the receiver. That's what I meant to say. Let's both read my post again.
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<br>The number of rings makes little or no difference once the case lets go. The brass gasket (case head) is the only seal in the breech. If that lets go, escaping (wild) gas is very destructive.

ken,
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<br>...my apologies, i must have misread/misunderstood your statement.
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<br>...in any case, i was just wondering whether the potential for case-head problems would be ameliorated by the weatherby system of..."[t]he recessed bolt face is surrounded by the barrel, which is surrounded by the forged and machined steel receiver" (weatherby 2001 catalogue).
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<br>...in other words, it seems (to a layman like me) as if a cartridge case set in a recessed bolt contained within the barrel and surrounded by the receiver ring may in fact assist in the prevention of escaping gases caused by a rupturing case head.
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<br>...just wondering whether weatherby's receiver claims have any real world validity.
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<br>...thanks again for your thoughts.
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<br>te
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So a cartridge case could be structured much stronger,than that which is currently employed?
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<br>Meaning that if a 404Jeff were to utilize brass,that was of double thickness in all areas,much higher operating pressures could be safely reached within the actions currently used to house that cartridge? That without other concerns,other than brass failure?
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<br>I find it interesting that ULA can utilize a reduced diameter boltbody and receiver,while still capably handling all the "high" pressure offerings now in vogue.
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<br>Any speculation on where the tradeoff lies in brass strength,verse lug sheer strength(or other mechanical action failure)?
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<br>This much interests me................

I'm reluctant to say much more, since I'm already dancing on the thin and crumbly edge of what I know about the subject. Besides, there's enough that's more easily knowable, that I can explore, to turn my attention to instead.
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<br>Re ULA, my feeling is that merely getting away with reducing the strength of actions doesn't endorse that reduction as safe or sane, or its results "just as good." "Dangerous" and "maximum" don't mean that the first shot with 0.1 grain more powder -- or with 0.001 inch less surrounding steel -- will blow the gun to bits. They mean that the some-day certainty of a burst gun is some indeterminable number of rounds closer, with the same lack of any way to know when it's GOING to happen with the next round fired. The margin of safety is thinner, narrower, shallower. I prefer that it be thicker, wider, deeper. Even if we could know very accurately, to the nearest foot per square inch of peak pressure or the nearest fraction of an inch of enclosing steel, it'd still be just plain good sense to stay well back from anywhere near the edge. So this discussion holds no interest for me. It's of no practical use or application that I can see -- especially in light of the great number of useful questions and well known subjects that so many handloaders and shooters seem woefully uninterested in thinking about or paying any attention to. I just don't understand the propensity of so many to ignore or minimize known good sense and safe practice, to spend instead so much time and thought wishing and wondering about how to play around with the impractical and dangerous.
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<br>There are already enough tigers waiting in the weeds to snag us, without any wisdom that I can see in putting more tigers out there.

My querry wasn't directed at throwing caution to the wind,but rather at the hope of understanding in greater detail,what actually makes things tick.
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<br>I've no fierce allegiance to ULA,but their design and success struck me as a nice place to start,when weighing relative size vs. relative strength. Especially if it has been deemed,that the brass cartridge case is in itself,the weakest link in the "safety chain". Their(ULA) actions are dainty as compared to most,well received and greatly respected upon many levels("strength",tolerances and quality of materials employed,foremost in my mind).
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<br>Despite being of less mass and diameter than a 96 Mauser,the ULA is chambered in all the "Hot Rod" offerings and I've never heard a hint of a complaint in any regard. Thoughts? Is it superior metallurgy,superior design,or just foolishness? I guess that was my point/question. More aptly,do the technological advances(ala ULA),offset the sheer mass of the '96? Is bigger always better? Is smaller always lesser,when concerning these issues?
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<br>My hopes were to understand,after reading your first Post upon the matter,that if wanting more performance why not look at adding more strength to case design,rather than keep making bigger and bigger cartridges that are of the same relative "strength".
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<br>Meaning,if the actions currently available are of overkill Engineering and the brass is the sole weak link,why not explore the obvious opportunities for performance enhancement? If the brass is the weakest link,why not fix it? I understand that some elasticity must be present,to make it jive,but am not convinced that cases as we know them could not be improved upon(regarding strength). That without negating the properties,that make brass a viable choice for the case proper.
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<br>Further,I would think that of the actions currently available,some are constructed of superior materials and design,as opposed to others. It would seem to me,that the most robust of those offerings,used in conjunction with a superior(strengthened) cartridge case,would easily yield enhanced performance and do so safely. As long as pressures were capably housed,isn't the margin of relative safety the same?
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<br>If that is not the case,I'd be curious to have an inkling as to how that is not so. If it is the case(literally),I'm equally curious as to why R&D isn't headed in that direction.
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<br>Any/all insight appreciated...................
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Regarding ULA actions - the way I understand it, they employ a combination of reduced receiver diameters and bolt diameters. Take this in combination with slightly improved metallurgy, or a different heat treat, and you may have an action that is the equal of a Remington in resisting failure due to the stresses caused by cartridge combustion pressure.
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<br>For that matter, they may not, and it may not make one bit of difference. My mechanical engineering classes are over 20 years behind me, and I never used 95% of what I learned, but I do remember the concepts of fatigue strength and service life.
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<br>Say that the weakest part of a receiver can sustain a stress of 120,000 psi before starting to yield. At 120,001 psi, low and behold, you've started to stretch that part of the receiver. So, at any stress greater than 120,000 psi, you've got a service life of one shot.
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<br>Now, at stresses of 110,000 psi, you may have a service life of 1000 shots before the receiver fails. At 100,000 psi - maybe 10,000 shots, and so on until you get to a stress level that will NEVER fail the reciever - infinite service life.
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<br>So, say that your favorite Remchesterby action has have a service life of one million cycles at SAAMI max pressure for the .300 Winchester magnum. Now say that the service life of the corresponding ULA action is only 200,000 cycles. Would you ever know the difference ?
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<br>As for increasing performance with higher and higher peak pressure, beware of the costs you'll be paying. Say you go to steel cases that can sustain 100,000 psi, and put them in an action that has a service life of one million cycles at that pressure. Said reciever will be more than one of the following: heavier, larger, more expensive. If you don't go with the beefed up receiver, you may have a service life of 10,000 shots - on average. Be VERY wary of the near end of that bell curve. And how many shots will your barrel last? Will it have to be larger in diameter to compensate for the increased chamber pressures ? Will current bullet technology be enough at the increased velocities ?
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<br>Besides Mr. Stick, you already have a 257 WSM on the way. Your life won't get significantly better until they perfect the laser rifle like they have on Star Wars
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<br>Regards,
<br>Scott
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I am old enough to remember the amazement that greeted PO Ackley's tests of Arisaka actions in the early 50s or late 40s, they were stronger than anything else, he tried tricks (as best I recall) like stuffing a couple of bullets in the barrel ahead of a loaded cartridge and the thing just shot them all out. 98s, 1917s, 1903s, 70s and 721s were not in the same league.
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<br>Why were the Japanese actions so superior?

I too remember that revelation from POA, but from then to now, I've known of no one who either (a) observed POA's tests (although some of my friends worked for him during that time) or (b) confirmed his results by repeating his tests. So I still have to wonder and must have some reliable confirmation before I can accept his claims as incontestable facts. I guess I'll have to get an Arisaka -- and a 94 Winchester to check another astonishing POA claim -- strap 'em to a tractor tire, and touch 'em off to see for myself. One advantage that I have, but he didn't, is the capability to instrument each rifle to record the internal pressures that will be produced during the tests. I'll also make sure to have enough reliable, technically knowledgeable witnesses watching, to see to it that my tests and their results are sound beyond serious question or dispute.
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<br>Anybody out there ready to risk sacrificing a rifle for a good cause? Any volunteers for "jury duty?"

Ken
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<br>I wouldn't doubt that POA did make those tests and reported them accurately. But, as Aristotle said, one swallow does not make a summer, and after half a century it would be interesting to see if they can be repeated. I too think I remember the 30'06? Model 94 that took tremendous charges. And Mike Petrov, who has been writing the classic custom rifles articles for Precision Shooting, made some astonishing tests on a Krag which swallowed amazing loads before bursting. I have misplaced the report but can probably get Mike to dig out a copy for you. I sent it to Dave Scovill but he declined to print it in Rifle or Handloader on the ground that some idiot would read it and immediately do something like barreling a Krag for 7mm Magnum.
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<br>miki

Dr. Howell- Now that's an experiment I could get behind! Kinda reminds me of some stupid things I did in my youth, which wasn't too long ago! A friend and I would 'experimenting' with various types of gunpowder, PVC, bolts, and a torque wrench! It's a good thing we had lots of fuse!!! We stopped when one of the bolts used to plug the ends of the PVC completely went through a tree that we were standing by! I'm suprised we never got arrested.

This is a facinating subject,of which I know nothing about.
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<br>I wonder where the Titanium receivers fit into this? Would the Remington ti receiver be much stronger?

Ken
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<br>Scratched thru the gun auction sites and there are 6.5 and 7.7 Arisakas galore, some of them rechambered to '06, .308, .300 Savage, 6.5/.257 etc., at all sorts of starting prices from 100 up. The more messed up the cheaper. With an original chrysanthemum on them they are actually $500 and up in decent shape. My vague recollection of POAs experiments was that the 6.5 was stronger than the 7.7 but the 7.7 was immensely strong anyway. Can't find my volume I of the Handbook. It ought to be possible to find really horrible ones of both types with decent actions at gun shows for $75, if we look long enough. But they are all post 1898 so if they are mail ordered or if I send a couple to you an FFL, dealer or c&r, is needed. I do get to a lot of gun shows and can start looking, am willing to cough up the really quite modest amounts required for this. But you would have to do the fun and games.
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<br>miki

The strongest breech would be unworkable as the heart of a usable rifle. It would comprise (a) a long, large nut* that the barrel would thread into from the front, (b) a threaded "bolt" that would lock the cartridge in the chamber (c) with the circumference of the case head totally supported by steel. The "bolt" would of course have to contain the means of firing the primer, but no extractor or ejector. The "receiver" nut would have to be too short for any loading-ejection port, and the chamber would have to have a sharp edge (no feed ramp) right smack-up against the face of the "bolt." Such an action would be easy to make on a small to medium lathe -- but sheer misery to load, shoot, empty, reload, etc.
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<br>*or a cup thick and solid across the rear, threaded to receive the barrel in the front
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<br>Sheer mass isn't the answer, nor is any of the other known metal alloys better than the best steels. Somewhere, I read how the burst strength fails to increase significantly past a certain thickness of steel surrounding the chamber.

Back to brass.....
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<br>Is there not room for strengthening brass cartridge cases(as we currently know them),while keeping them "workable".
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<br>If said brass were used in the typical "modern" actions we now take for granted,could they safely operate at higher pressure levels,than those which are currently deemed as "safe"?
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<br>That question has been nicely sidestepped..............
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Ken, I may be mistaken but the action you describe sounds quite similar to the magnum research "Lone Eagle" single shot pistol. They have a screw in breach and a seperate cocking lever that has to be worked to fire it.
<br>I agree they are a pain to load but they sure put - um where you point.
<br>I`m under the impression that some artillery uses a interuped thread, screw type breach also.

Stick,
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<br>It depends on the diameter of the case. I'm of the opinion that it is a matter of time before we start hearing about more and more rifle failures, as they larger dia cases, ie 404 based and larger are becoming commonly available to the average hand"over"loading nimrods.
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<br>As brass dia increases, the chamber is thinner, and the stresses are higher at the same pressure as a smaller case, and the backthrust on the bolt increases. We are still using the same actions designed for the -06 and 375 case head rounds, but now folks are pushing them harder with the larger cases.

<br> I regards to building a "small ring" Mauser with "better steel; The Springfield 03 is a copy of a 93 . In fact a 93 will practically fall into a 03 stock. The early 70 Win is another. Mauser used design to make up for strength. The small rings are strong enough, but will not handle case head failure safely. When the case goes gas ect comes back down the left bolt raceway and into, your face. I have seen small rings that have let go over the right bolt raceway due to gas pressure. They don't fail due to too little metal around the cartridge, or only having two lugs.
<br>Good Luck!