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Pressure, the 6.5x55, the 7x57mm and old Mausers

Discussion in 'Rifle Country' started by 35 Whelen, Dec 28, 2011.

  1. 35 Whelen

    35 Whelen Well-Known Member

    It seems more and more there are discussions on this forum regarding the pressure limitations of older Mauser rifles. Lately, there have been a few discussion centered around the 1916 Mauser, the fact that many are available chambered in such relatively high pressure rounds as the .308 Winchester, and the supposed "facts" that this type Masuer actions is a ticking time bomb when so chambered.
    The most regurgitated internet "fact" is that the 7x57mm cartridge is rated by SAAMI ( Sporting Arms and Ammunition Manufacturers' Institute ) at 46,000 CUP or about 51,000 PSI (There's no way to convert CUP to PSI or vice versa).

    When I see these "facts" posted by supposedly informed individuals, I can't help but wonder how many people realize that the 7x57 is about 34 years older than SAAMI (Est. 1926) and how many realize that said cartridge is of European descent? In other words, pressures for the cartridge were established LONG before SAAMI was founded and decided that said 7x57mm cartridges loaded on American soil should be limited to 46,000 CUP. I also wonder how many Mauser and Mauser cartridge experts have heard of "CIP"?

    CIP (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives )is the European equivalent of SAAMI. I'll not go into great detail about them as there's plenty of resources on the 'net. But to get to the point...

    There's an excellent write-up, with non-internet references, on Wikipedia. Here's an excerpt(pay special attention to the last sentence):

    "According to the official C.I.P. guidelines the 7×57mm case can handle up to 390 MPa (56,564 psi) piezo pressure. In C.I.P. regulated countries every rifle cartridge combo has to be proofed at 125% of this maximum C.I.P. pressure to certify for sale to consumers. By contrast, the American industry association SAAMI specifies a lower maximum pressure of 46,000 CUP or 51,000 psi.[4] Although this lower specification is in deference to the purportedly weaker actions of the older Mauser 93 and 95 rifles which are still in circulation,[4] this concern is misplaced, as the original ammunition developed for, and issued with, the M93 Spanish Mauser produced an average pressure of 50,370 CUP in those rifles.[5] [6]"

    Hmm....kinda goes against the accepted internet forums info, eh?

    Likewise, regarding the 6.5x55:

    "The CIP MAP for the 6.5 × 55 is 380 MPa (55000 PSI). SAAMI MAP for this cartridge is 46,000 CUP or 51000 PSI.[2] All Swedish Mauser actions were proof-tested with a single 6.5 × 55mm proof load developing approximately 55,000 CUP (66,000 psi).[3]"

    Now, where did the rumor start that the older Mauser actions, ESPECIALLY the '96 Swedish Mauser, was designed for a 46,000 CUP cartridge?

    For those of you that are handloaders, it doesn't take much research and extrapolation into the original loadings of either of these cartridges to realize that in order to obtain the ballistics they obtained, especially with the limited powders of 80 or so years ago, (remember, in the early part of the 20th Century, slow burning powders such as 4350's and 4831's had yet to be developed) the loads HAD to exceed SAAMI's 46,000 CUP.

    Just a little food for thought...

  2. gunner69

    gunner69 Well-Known Member

    Great Write Up......

    Most, if not ALL, European loads excede the power of the US makers for the same calibers. I own several of the older European calibers but don't load "hot" for them out of said safety issues. Do I think it will blow up my gun? No, but I am being "over" safe.

    As long as I am not shooting +P loads I am really not worried much. I have hunted in Europe and used their ammo with narry a problem. Would I shoot their loads in the 100s or 1,000s? Probably not, but then I would not shoot +P ammo in my handgun for general/practice use either. The "good stuff" is for the kill.....
  3. willypete

    willypete Well-Known Member

    FWIW, I've read a lot of similar stuff regarding 6.5x55 Swede and have decided that my Carl Gustaf 38 will handle "modern" loads with slow burning powders (7828, 1000, etc.) with proper work ups. No problems so far, shooting both my reloads and European factory rounds (Lapua, Prvi).
  4. PedalBiker

    PedalBiker Well-Known Member

    SAAMI is an organization set up by the manufacturers, not the consumers.

    I think it's the fact that loads of 100 year old guns are still around, not the fact that 100 years ago (when they were new) they could handle full power loads.

    Given the fact that most US manufacturers don't turn out a lot of modern arms with the metric cartridges, it just boils down to the numbers, many folks are buying ammo for really old guns.

    If there were more modern arms chambered for the Xx57 and 6.5x55 would there be more full power ammo? Handloaders are ubiquitous and solve the problem themselves.
  5. morcey2

    morcey2 Well-Known Member

    The one that drives me nuts is the 8x57 SAAMI rating. 36000 CUP? Really? I know the reasoning behind it, but I've seen my share of M88 Commission rifles but I've never seen one that hasn't been converted to safely shoot .323 bullets. I'm not sure if any of the unsafe ones really existed! (I know they did, I don't think the numbers justify the solution.)

    I shoot lots of Yugo surplus w/ 196 grain FMJBT bullets that are usually in the 2450 FPS range. Domestic Win/Fed/Rem loads are 170 Grain@2260/2350 FPS? Round Nose? Really? That's 30/30 ammo without the cool lever action. Prvi Partizan is slightly better, but not much. If you get the boxes marked "8mm Mauser", it's still pretty anemic, but at least it's a 196 grain pill moving at 2360. That's not too bad. The "8x57 IS" marked boxes are quite a bit better. But at least it's reloadable. I've got a couple more that I need to try: Gold Wolf, BVAC, Norma, S&B...

    I'm building a 6.5x55 on a Spanish M93 action and it'll probably be loaded relatively mildly. The other one I'm working on right now is a 257 Roberts on a Yugo captured K98 receiver that I'm sure can handle full 257 Bob +P loads and then some. I also have a Mexican 1910 small ring 98 sporter in 7x57 that is currently my main deer/varmint/squirrel/clueless-teenage-boy-pursuing-my-daughter gun. I've probably got a little less headroom on that one with most off-the-shelf ammo, but it is a small ring, even if it is a 98.

    Once I get fully equipped to reload all of them, I'll probably stop complaining. Maybe.. Hodgdon's website lists what looks like some pretty hot loads velocity-wise for all of the above, but they seem to have reasonable pressures.

    I'll quit rambling now since my cold medicine seems to be kicking in. I can tell because the voices in my head start making less sense than normal.

  6. R.W.Dale

    R.W.Dale Well-Known Member

    None of which changes the fact that the rifles in question are OLD sometimes in questionable shape and tend to handle failures very poorly from the standpoint of the shooter.

    At some point a limit has to be established for the sake of safety. Just because you don't agree with it doesn't mean its not there for a very good reason. After all in the case of the worst we're not talking about an inconvenience that merely messes up a $200 rifle. This is something that can KILL YOU. Even Paul Mauser himself lost an eye to pushing the envelope with HIS OWN DESIGNS

    308 win is about as hot and has as much bolt thrust as anything on a .473" casehead. It is to this day almost at the limit for metallic cartridge pressures. I don't think anyone here will argue that a small ring Mauser is as strong as the platforms Winchester or the army had in mind when developing 7.62/308

    Which brings us full circle if 308 was designed for much stronger actions then what is the limit for the small ring? Well its what the actual ballisticions at saami recommend vis-a-vis pressure ratings for the original chamberings. Any way you try to slice it the fact remains that the SAAMI piezo rating of 62k psi IS STILL HIGHER by 5000psi that even the highest cip piezo rating for 7x57mm.

    All of which assumes the two bodies use the same calibration for their pressure trace

    posted via tapatalk using android.
    Last edited: Dec 29, 2011
  7. Ignition Override

    Ignition Override Well-Known Member

    Was there no general correlation between military cup and Saami psi?

    If not, then has 7.62 NATO ever been rated at about 58,000 max. average psi, or is the figure always much lower than commercial US .308. (62,000 psi or so)?
  8. 35 Whelen

    35 Whelen Well-Known Member

    Wondered how long it'd take you to respond.

    What prompted my research was the often mis-stated "these actions ('93, '94, '95, '96. etc.) were designed for cartridges that develop no more than 46,000 CUP" B.S. And sure enough, that statement is just that... recycled, internet B.S.

    The .308 wasn't "designed" for or around the pressure limits of a particular action. If it was, then it'd been loaded to even higher pressures than it is. The .308 was simply designed as a shorter cartridge similar in power to the 30-06.

    Have you taken the time to read this thread:7.62 NATO Pressure vs. commercial 308 Winchester? Very interesting stuff with some good insight regarding actual chamber pressures of the .308 and 7.62x51. If you do take time to go there, read the entire thread, please. I think you'll find the .308 isn't the high pressure hot rod you think it is. And incidently, the .270 Winchester, first chambered in way back in 1925 (ironically, about the same time some of the actions in question were manufactured), has a maximum pressure of 65,000 PSI, or almost 5% more than the .308.

    My Lyman 49th Edition has .308 loads listed in both CUP and PSI which is quite nice for making comparisons. While it is established that there is no direct conversion from PSI to CUP and back, by comparing CUP figures to PSI figures in loads using the exact same weight and brand of bullet, we can see something of a pattern. Generally speaking, Lyman maximum loads over all of the loads is 61,000-ish in PSI with the vast majority being under 60,000 and 51,000-ish in CUP with more loads UNDER 51,000 CUP than over. Hmmm....the CUP figures for the .308 are only slightly higher than those established by C.I.P. for the 6.5x55mm (55,000 PSI) and the '96 Mauser action, and within 1000 CUP of the C.I.P. established pressure for the 7x57mm (50,370 CUP).

    It's late, and I'm going to bed and sleep peacefully knowing that my wife's 1916 in .308, with its proper headspace, is perfectly safe to shoot with commercial ammunition should the need arise.

    Last edited: Dec 29, 2011
  9. 35 Whelen

    35 Whelen Well-Known Member

    No, no correlation. Please click the link in my post above and read the thread on the .308/7.62x51mm. Interesting, fact-filled stuff.

  10. R.W.Dale

    R.W.Dale Well-Known Member

    Again none of which changes thr fact in the slightest that 308 is about 10% hotter than even the highest pressure military metric cip cartridge.

    Yes 270 is slightly hottet and you know what it couldn't have been done till Winchester introduced the 54 made from Winchester proof steel.

    When did you buy a set of headspace gauges?

    At the end of the day I recommend to anyone to download for pre wwi guns. Because how safe they are isn't borne out by how well they handle a load when everything is perfect. But rather what the consequences are when something goes awry. A flawed case head or a blown primer on a Remington 700 is an attention getting event that can cause damage to the rifle that may need repair. That same event with a small ring Mauser will probably send you to the hospital and if not wearing eye protection will cost you your vision in at least one eye.



    It does happen!

    Is your wife's vision worth betting on some anonymous internet poster of unverified credibility or your own quest for positive reinforcement for something you're already doing against sound warnings? All I can say is I sincerely hope not.

    posted via tapatalk using android.
    Last edited: Dec 29, 2011
  11. USSR

    USSR Well-Known Member

    35 Whelen,

    You are correct in your assessment that the 6.5x55 and 7x57 cartridges were not designed to be the low pressure rounds that American ammunition manufacturers now load them to. The loading down of these two cartridges is in deferrence to the weakest link in regards to available rifles in that chambering. In the case of the 6.5x55, the weak Norwegian Krag action chambered for that cartridge, and in the case of the 7x57, the occasional Remington Rolling Block rifle in that cartridge. There is nothing inherently weak about the case itself, and in a modern gun, both can be easily reloaded to the normal 60k psi pressure level that any modern bolt action can handle. With my 6.5x55 M70 Match Rifle, I can easily load 139 - 142gr Match bullets to 2950fps.

  12. R.W.Dale

    R.W.Dale Well-Known Member

    I agree with this. In a MODERN FIREARM there's no real reason every .473" case cartridge can't be loaded to 270 pressures. When I had a interatms markX in 7x57 I simply dispensed with the milktoast 7x57 data and loaded it like it was a 7mm08

    But this isn't the point 35w is driving at. He's trying to justify hot loads in an OLD firearm just because higher pressure loadings exist.

    Would you fire your match loads in an m96 Swedish Mauser for example?

    posted via tapatalk using android.
  13. USSR

    USSR Well-Known Member

    Only if the M96 was tied to a tire with a long string attached to the trigger.;)

  14. Gunnerboy

    Gunnerboy Well-Known Member

    This is why i use Norma reloading standards rather than any American stuff for european rnds they actually have thier full potential when you load them the way they were meant to be
  15. R.W.Dale

    R.W.Dale Well-Known Member

    Speaking of Norma what is that pictured to the upper right of the screen on their reloading disclaimer page?


    posted via tapatalk using android.
  16. Hummer70

    Hummer70 Well-Known Member

    I remember at Perry one year when Springfield Armory ( the real one in Springfield, Mass) had a display at Camp Perry. This would have been 57-60 time frame.
    The took about two dozen old Mausers and placed the cleaning rods from them down in the barrel touching a live round and fired it under a proof hood.
    Several barrels failed, no actions did.

    I think it is Hatcher's Notebook about a guy that put a 30.06 chamber in a 6.5 Jap and fired it and action held. The guy that did it was a friend named Billie Merredith who was match pistol armorer at Quantico for Marine Team. He had a 30.06 reamer that was shot so he ground the pilot down to go in a 6.5 barrel and chambered it and fired it with a lanyard from behind a barrier. The barrel moved forward bout two threads but action held.

    I have never heard of a catastrophic lug failure on a bolt gun that the heat treatment wasn't altered but I have heard of multiple barrel failures.

    There was an article about a 1903 Springfield that blew up in the Rifleman back in 60s I think. Guy sued the gov't saying it was an unsafe rifle.

    The rest of the story was told to me by the gov't expert witness who was a very good friend named Larry Moore. He said he got on the stand and the plaintiff's lawyer asked his name and position and then the screwed up, he next asked Larry to outline the development of the Springfield 1903 and Larry asked him if he wanted a brief overview or in depth survey. Lawyer screwed up again and said a brief overview would be fine.
    Larry talked for five days on that one question and took nearly 500 pages of court transcript to type it up not including the charts, drawings etc. Lawyer stated he had no furthur questions. Jury was out about five minutes and came back and said the gov't did no wrong.

    Dumb S&*T took a 03A3, heated receiver ring red to mount front scope block. Rear ring red to mount rear block. Then he put on a Griffin and Howe side mount after heating receiver red. Next he opened the bolt face and chambered it in 308 Norma Magnum and loaded it with a 30% overload. Went out and sighted it in and held.

    He went hunting about 0 deg F and fired the first round at a deer, rifle let go, bolt went through guys face and tip of his nose wound up about even with his wisdon teeth and lived through it.

    In Larry's testing prior to the lawsuit he duped what the guy did for loads and chambering but not heating the action and fired hundreds of rounds in testing and 03 held.

    Small and medium case head rounds sustain massive plastic deformation about 90,000 pounds and it is estimated melt about 115,000.

    I once did a malfunction investigation when I was with Army Small Cal Lab. M16 had let go expanding upper and lower receiver blowing mag into soldiers arm. The bolt and the barrel socket were fine. Extractor was gone. Couldn't see down the barrel and there was no case sent in. Took it to X ray and came back with a X ray of a 55 gr. FMJBT bullet nose to nose with a cleaning rod jag and patch on it. Barrel was not even visably swollen.

    I read just the other day the M16 was a weak system. BS ! ! ! !
  17. RevGeo

    RevGeo Well-Known Member

    Pretty interesting stuff. I haven't shot a factory round in any of my rifles - excepting .22 rim fire of course - in many years. As a Mauser freak I have loaded for many of the older guns such as the '93, '94, '95, '96 and '98 (I wonder what happened in 1897?) using data from the usual sources. What the pressures are number-wise don't make much difference to the handloader as long as he/she watches for the usual high pressure signs, IMO.
    I've loaded some stuff for a Swede carbine in 6.5x55 that was probably pushing 2900fps with no signs of excess pressure. Same with the 7mm and
    As 35W rightly points out, the cartridges are not inherently weak compared to more 'modern' rounds. And I personally think the '93 and '95 actions are plenty strong, even without the added locking lug of the '98.
    As long as the rifle is in good shape, even at over 100 years of age, I have no problem loading them up while constantly watching for any signs of excess pressure.

    The American rifleman who shoots factory ammo exclusively is stuck with rather anemic loads in the fine Mauser calibers, but at least the factory loads are a good source of brass:D.

  18. 35 Whelen

    35 Whelen Well-Known Member

    Wrong. I'm not trying to justify anything, rather put to rest some of the beauty parlor type, internet myths perpetuated by uninformed "experts" spouting undocumented, unverifiable, unreferenced facts. Myths such as "...the '93 Mauser was designed around a 46,000 CUP cartridge...":barf:

    Yet in spite of the referenced material presented here including a test by H.P. White labs, some refuse to open their minds to the possibility that they might have been wrong or at least mislead.

    And no Mr. Dale, I don't own a set of headspace guages. As an experienced handloader, I know the signs of excessive headspace without having to use a headspace gauge. (I've owned a few SMLE's that came to me with slightly excessive headspace...Neck size, son, neck size.) Since you evidently don't know the signs, shoot me a P.M. and I'll explain them to you. Then you can sell all your headspace guages and use the money to buy Xanex for when you shoot your Mausers. ;)

    RevGeo summed it up VERY well. Read his post, follow his lead, and everything will be fine.


    P.S.- Mr. Dale, you reference a picture on the Norma website of a damaged '96 Mauser. Were you aware of the fact that Norma uses this action for load development?

    From the Dec.2009/Jan.2010 Handloader Magazine:

    "I set up a pressure barrel and fired a round. "Errr, sir, better not fire another." came from the technician. Pressure was a rather enthusiastic 81,000 psi. The equipment is only rated up to 65,200 psi! It says a lot for the old 1896 Swedish Mauser action that the pressure barrel was screwed into that it didn't let go and there was only a little stickiness when I opened the bolt."

    The above statement was attributed to:

    Dr. John Heath
    D. Sc. Technical Support
    Norma Precision
    Last edited: Dec 30, 2011
  19. crazysccrmd

    crazysccrmd Well-Known Member

    The Wolf Gold is pretty good, a 196gr SP moving about 2500fps and is PPU brass, might just be relabeled and not actually Wolf production. The S&B is good as well, 196gr SPCE (weird stepped design) moving about 2600fps. Both of their brass is reloadable but the Wolf (PPU) is much higher quality. It is easier to resize, prime and was closer to spec in length out of the box than the S&B.
  20. willypete

    willypete Well-Known Member

    Thank you, 35 Whelen. I love to see a logical argument backed up by facts, research, and citation. It's all the more enjoyable when it decisively pulls the rug out from tenuous internet rumors and those who proliferate them.

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