308 win in 1895 Chileno??

[CHeatermk3]

Looking at a Chileno on GB seller claims it's in 7,62x51?? Were any Chileno mausers 7,65x53mm?

Would this even be safe in the M1895 action?

[Texas by God]

They were rebarreled or rebored to .308 or the CETME 7.62x51. They were originally 7x57. Some say they're safe and some don't. I would treat it like the action is 100 yrs old and reload to the design pressure. All the 95's I believe are German so that helps.
Best, Thomas.

[Skipper]

Read this before you pull the trigger

http://dutchman.rebooty.com/1895Chile.html

[Texas by God]

Great post Skipper. I revise my advice to rebarrel that action to a small ring certified cartridge. Lots of great choices but hard to ignore the original 7x57.

[CHeatermk3]

Skipper, thanks for the link! The pix of the "El Supremo" make me drool!

I decided to pass on the "308" Chlieno Mauser as I could not fathom the 308win in the 1895 action--from what I gathered reading the Dutchman's info, the original 7x57 barrels were rechambered to 7.62 Nato? With a 7mm bore?

I have a Chileno in 7x57 and love it the way it is--bore is kinda frosty but I'm workin' on it. Got it from a member here and the wood looks plain but very clean and nice.

I bid on the rifle in question before I noticed it was stamped "7,62" on the reciever bridge (also the seller said it to be "308 winchester") and I failed to notice that too.

I have passed the link supplied in post #3 to the seller with advised him to caution the buyer against shooting commercial 308win ammo(or anything not severely down-loaded!).

[racepres]

Said it many times but...
I have been shooting my CETME Spanish 1916 [model '93 small ring] for years...
I handload Only, and I use approximate 300 Savage loads..
While I love the 7X57 Many folks will tell you that 300 Savage is OK, or even preferred...
I like the CETME with Savage loads because it has a Longer neck, and I prefer Cast lead Boolits!!!
But...For Factory loads....You should Pass!!!!

[Multigunner]

"from what I gathered reading the Dutchman's info, the original 7x57 barrels were rechambered to 7.62 Nato? With a 7mm bore?"

They rebored the barrels to 7.62, but due to the 7X57 being a longer case they had to bore the front of the chamber deeper to accept a chamber adapter similar to the operation used by the USN to convert .30-06 Grands to 7.62 NATO.
The chamber insert is just soldered in place and sooner or later the adapter develops problems due to gas cutting of the soldered joint.
NATO M80 Infantry Ball is not a very high pressure cartridge, only 48,000 CUP, but M118 and similar Special Ball and Long Range cartridges generate much higher pressures unsuitable for the small ring Mausers. M118 generates pressures very close to the 58,000 CUP proof test loads used for the 1888 Commission Rifle and the early Small Ring Mausers. Some Long Range Match loads for the .308 exceed the pressure of the proof test loads.

[racepres]

I like Loads of 300 Savage pressure in the 7.62 NATO Small rings
BUT!!!



I prefer Cast lead Boolits!!!
For Factory [or Military, or Target...or any Commercial] loads....You should Pass!!!!

[Larry Gibson]

190458

First of all let me say I'm not accusing anyone of lying.......it is the point of the quote I'm making.

M95 Chileans were converted to 7.62 using two methods; first was, as the link to Dutchman's article shows, was by drilling out the 7x57 chamber and solder/brazing an insert in it, reboring and rifling the barrel to 7.62 and then rechambering to 7.62 NATO. This was not a safe conversion. However the second method was to rebarrel the M95s with a new 7.62 barrel. Those conversions are safe to use with .308W and 7.62 NATO.

Unfortunately Dutchman repeats data, by quoting other sources, attempting to show that .308W generates a lot more pressure than 7.62 NATO. The data he gives is essentially correct but it is misleading. The SAAMI MAP for the .308W quoted (62,000 psi) is that. The U.S. Military spec MAP quoted for the 7.62 NATO is 50,000 psi. So what is misleading about that? It's apples vs oranges; the SAAMI MAP for the .308W measured with modern transformal peizo-transducers. The psi MAP for the 7.62 NATO is from 1950s Copper Unit Crusher (CUP) psi measurement. If we look further into SAAMI information we find they also list a CUP MAP for the .308W. It is 52,000 psi.

Thus in reality we have very close MAPs of 50,000 and 52,000 psi with both measured by the same. I have measured the psi of numerous U.S. and foreign 7.62 NATO cartridges and numerous .308W factory rounds and find the actual lot to lot MAPs of .308W and 7.62 NATO overlap so much it is almost impossible to say which actually has the higher psi. Just this morning I measured the psi and velocity of my reference lot of M118 SB. It ran it's usual 61,000 psi +/-.

This brings us to another untruth told so often every one believes it; "Mauser designed the SR actions for 45,000 psi".....Problem with that is Mauser did not measure "psi"s and even the CUP method of chamber pressure measuring was not in use then. Mauser designed and made the SR Mauser actions as strong as he could given the metals and technology of the day. Cartridge design was in it's infancy and cartridges were loaded to be safe in the actions they were made for. So where does the 45,000 psi come from? Darned if I've been able to track it down, that statement has been repeated so often it's become the "truth". What I do know is I have measured the psi of numerous milsurp cartridges made for SR Mausers (6.5 Swede, 7x57 Mauser, 7.62 CETME, 7.65 Belgian and 7.65 Argentine) dating back to 1918 (Spanish made 7x57). They all had MAPs of 53 - 60,000 psi. European factory loads for the same cartridges have essentially the same MAPs as their milsurp counterparts. Seems to me there would be a lot of blown up SR Mauser rifles if they were "only safe for 45,000 psi". I've yet to find a milsurp 7x57 the generates less than 51,000 psi.

I have found several non NATO spec 7.62 cartridges that generates 45,000 to 53,000 psi for use in those countries with HK M91s and for one country that had FN-FALs.

Another "truth" that has been told so often about the FR7 and FR8 rifles is they were "designed for the 7.62 CETME cartridge". I'm sure you've all heard that one as it is repeated often on this forum. We all know the 7.62 CETME is a low pressure load to be safe in those rifles which were only designed for 45,000 psi.....right? Well I happen to have come across a quantity of original Spanish made in 1962 7.62 CETME ammunition. I pressure tested it in the same test rifle I shot the M118 SB in this morning......guess what the 7.62 CETME's MAP was? Well it wasn't below 45,000 psi and it wasn't 300 Savage level either.....it was 60,000 psi for a test string of 10 cartridges (I will post the Oehler data sheet for the non believers if they'd like?). Yes, I know we have been told over and over again the CETMA cartridges had lower pressures that the 7.62 NATO. Problem is they don't....the German engineers who came up with the CETME cartridges to solve the extraction problems in the then unfluted chambers of the CETME rifles altered the time/pressure curve with a faster burning powder and were able to maintain the recoil impulse to function the delayed roller blow back action of the CETME rifle by using a lighter weight bullet and redesigned rollers. The actual operating pressure of the ammunition had to remain the same for the CETME rifle to function. But we have been told over and over again that the FR7 and FR8s, regardless of what the Spanish manual for those rifles says, are not safe with 7.62 NATO ammunition but only with 7.62 CETME psi level ammunition.......since they are the same psi level is there really a difference?

I recently came into some actual Chilean 7x57 cartridges they made for use in their M95s. The armory they were made at in Chile is over 200 years old and still is producing quality arms and munitions btw. I will be pressure testing it in my own M95 Chilean 7x57 next week and will report the results......should prove interesting.

Larry Gibson

[CHeatermk3]

Is there any way to tell whether a rifle has been re-barreled or re-bored and chamber plugged? Without breaking it down?

Glad I passed anyway--gun went for $205 ++

[Multigunner]

"even the CUP method of chamber pressure measuring was not in use then"

Are you sure of that?
The oldest copy of W W Greener's book "the Gun and its development" that I've found so far mentions the CUP method in use by Germany at that time. The Copper Units method was a French invention. CUP pressures were converted to Metric Atmospheres, same as the British BAR designations. Both Metric Atmospheres and BAR are easily converted to CUP or PSI according to the method used in testing.
Greener explains the German method of establishing Proof Test pressures based on the expected pressures of degraded ammunition fired in a very hot tropical climate. Rather than increasing the powder charge, which reduced capacity, they formulated special powders that mimicked degraded powders.

The USA was still using a method where a steel chisel headed spike was driven by chamber pressure into a block of copper. The penetration of the spike was measured to get a pressure reading. That method is so antiquated that I've never found much about it.

An account of the Gran Chaco War tells of older small ring actioned rifles failing when 1930's ammunition loaded for 98 actioned rifles and MGs was used in the older rifles.
By 1915 DWM was manufacturing a cartridge intended for 98 actioned 7mm rifles that launched a 154 gr bullet at over 2900 FPS. I doubt very many 93 or 95 actions could handle those.

Years ago I ran across accounts of testing of captured Spanish American War era 7X57 ammunition, including attempts to develop an identical load using American made smokeless powders of the day. I don't remember there being much in the way of modern pressure levels in those tests.

As for US Army ammunition technical manuals many contained bad information and were constantly being updated and revised. The best source for chamber pressure specs of the various 7.62X51 NATO cartridges is the propellants procurement data sheets. These give allowable pressure ranges in both CUP and PSI EPVAT except for M118 Special Ball which is expressed in CUP only.

[Larry Gibson]

Yes I am sure. The CUP method was also in developmental stages along with smokeless powder cartridges (also in ther infancy and early developmental stages) and their higher attendant pressures in the 1880s and 1890s. The basic method of CUP pressure measurement used for the next 100+ years did not come into general use until the mid/late 1890s after several articles appeared in a couple of the scientific journals of the day (they can be found through google). Refinement of the CUP system wasn't complete until after the turn of the century. Note cartridge case development and refinement continued to have safety issues through the early 1900s. It was those issues that prompted many of the safety features found on the M98 action that aren't on the SR actions.

Mauser had the basic design of the SR actions completed by 1888 and the M92/M93s were produced in those years meaning they were developed before then. The M95 and M96s were refinements of the basic SR action as better steels and heat treatments were developed. It was not the design of the Mauser Actions that held pressures lower in the early smokeless cartridges but the powders and case itself. It wasn't until newer more consistent powders were developed along with brass and case manufacturing technology over the next century and even continues today that the higher magnum level of pressures became containable. However, the Mauser actions were quite able to contain and maintain service capabilities with cartridges of 50,000 CUP psi (60-62,000 psi as measured with transducers).

We hear lots of tales of "machine gun" ammunition loaded to higher psi. Yes there were a few documented cases of that. However, military ammunition packaged in boxes of 15 rounds (the amount per ammo pouch commonly used) in 5 round Mauser stripper clips was intended for Mauser rifles, not machine guns. The 1918 Spanish made 7x57 cartridges I tested had the 174 gr cupro nickel RN bullets and were in stripper clips. The European C.I.P. MAP for the 7x57 is 57,000 psi (transducer). The 1918 ammo ran a psi of 56,500 in my M95. I also tested some of the 154 gr so called machine gun loads and they did run a little hotter at 59,400 psi. Even Remington and Winchester factory 175 RNSPs exceeded the SAAMI MAP of 46,000 psi (transducer) running at 47,900 and 49,900 psi. Checking my records I did find 2 loads that did not exceed the SAAMI MAP; one commercial and one milsurp. They were Hornady's Light Magnum and Venezuelan CAVIM 7x57.


As I said it will be interesting to see what the Chilean made 7x57 will run out of a M95 as that's the rifle it was made for.


190501

If using the NATO EVAT pressures listed for 7.62 NATO ammunition it is also a apples vs oranges comparison with SAAMI or C.I.P. pressures as the EVAT transducer measurements are taken at the case mouth not the middle of the case body as are the other two. Still those are much closer and a more valid comparison than attempting to correlate CUP measurements with transducer measurements. The EVAT MAP (they call it a MPa/psi) for M80 ball is 60,190 BTW.

It is an incorrect assumption to believe every cartridge is loaded to the MAP. It isn't done that way. Most military and commercial cartridges are loaded to a velocity/accuracy standard (surprisingly there is a rather large +/- to that standard) while maintain less than the established MAP. Some, given the nature of the lot of powder used, are close to or at the MAP. Newer modern ammunition, given the unforeseen variable the ammunition will be used at, the actual pressures the ammunition is loaded to is usually less than the MAP giving a "fudge" factor. However, in days of old pre SAAMI and CIP many were loaded to maximum pressures for the cartridges, even those for use in SR Mauser actions.

Larry Gibson

[Texas by God]

Let's not forget all the 1893 Turk 7.65s converted to 7.92x57. They seem to hold up.
Best, Thomas.

[Larry Gibson]

And all the Turk '30s, '40s and '50s milsurp I've pressure tested has been in the 56 - 59,000 +/- psi range. Same as German pre and WWII era 8x57 milsurp.

Larry Gibson

[Multigunner]

Well now we know why so many 93 and 95 Mausers are found to have serious lug setback.

[Texas by God]

I think the point being made is that a good shape SR will hold up to .308 pressure levels but not a good idea for a steady diet. After all we want that action to last another hundred years.
Best, Thomas.

[Larry Gibson]

No, M93s and M95s probably should not see a steady diet of any loads that go over 60,000 psi (transducer). Personally I keep jacketed bullet loads in the 54 - 57,000 psi range for use in my own SRs (M91s, M93s, M95s and M96s). Of course normal cast bullet loads and even HV ones won't get anywhere near that psi range.

As to lug set back we seldom know the real firing history of such actions. Prior to obtaining the Oehler M43 I had several "excellent" loads worked up years ago for several cartridges (.223 Rem, 6.5-280, .308W and 30-06) using the old methods proffered in loading manuals and in magazines. All but the 6.5-280 were within recommended loads in those older manuals. The 6.5-280 load with H4831 under a 129 gr Hornady was generating over 67k psi. After 2,000+ rounds of that load the lugs in a M98 Mauser had set back .001 - .002". I have seen several M93 FR7s with some lug setback. After discussing the ammo used while they had shot a lot of 7.62 NATO (U.S. M80 ball) they ad also loaded max .308W loads out of manuals (none had bothered to work up loads) and shot quite a few.

The .223, .308W and 30-06 were pushing 64 - 68k psi! It's why I suggest most reloaders stay within loads of the newer manuals that adhere to SAAMI MAPs. Those with wildcats or with a lot of experience may venture outside of that parameter if they have firearms made for higher pressures chambered in older cartridges such as the 45 Colt, 35 Remington and 45-70, etc. When doing so great care should be used along with a chronograph. No, the chronograph will not tell you the pressures but if you find velocities higher than expected then there are attendant higher pressures.

As when the use of CUP pressure measurement came into general use (as we know it) and what pressures Mauser may or may not have designed his actions for I have researched it for many years. What I found is basically stated in the previous post. However, should anyone have other documented information I would certainly like to see it. I am always learning and am very will to change my findings when new facts are found.

Larry Gibson

[bouncer50]

Well now we know why so many 93 and 95 Mausers are found to have serious lug setback. That is true. I have seen a few FR-7 in 308 lug setback. I myself if i had one it would be a castbullet shooter. Hell the steel they used is over a 100 years old now. With modern steel the 93 and 95 would be safe in 308 in my humble opinion.

[Multigunner]

Here's a Report to the Chief of Ordnance 1898 on testing of captured Spanish Mausers and the 7X57 cartridges captured in Cuba.

https://books.google.com/books?id=YgFHAQAAIAAJ&pg=PA179#v=onepage&q&f=false

In attempting to duplicate the ballistics of the French and German manufactured Ball cartrdges, using the cartridge cases and bullets of the respective origins but the charge replaced by the then current Dupont manufacture No 9 Smokeless powder, they found the Dupont powder generated less chamber pressure and less variation in chamber pressure.

German cartridges varied in pressure from 43,200 CUP to 51,150 CUP, with only 39 FPS difference in velocity between the two. The French cartridges varied from a low of 48,250 CUP to a whopping 55,800 CUP with the lower pressure giving the higher velocity of the two.

When loaded using Dupont No.9 powder the chamber pressures did not exceed 42,100 CUP with a low of 35,450 CUP.

[Larry Gibson]

Multigunner

Thanks for the inclusion of that information. I have read and studied that report and some similar ones from the same time period. It and the others were the basis for my statement; " The basic method of CUP pressure measurement used for the next 100+ years did not come into general use until the mid/late 1890s after several articles appeared in a couple of the scientific journals of the day (they can be found through google)".

Noting the 43,200 CUP to 51,150 CUP of the tested German 7x57 ammunition which was what the Mauser SRs (M92, M93 and M95s) were made to use we see a good correlation to the MAP of 50,000 CUP for the 7.62 NATO. Those German CUP psi's also conform to the transducer psi measurements of 50,000 to 60,000 psi that I have measured in the corresponding milsurp 7x57 and 7.62 NATO cartridges. Note the test report stated no damage was done to the Mauser rifles which I assume to be M93s, probably captured in Cuba.

Larry Gibson

[Multigunner]

The wide variation in pressure readings of the German manufacture 7mm ball leads me to believe that particular lot of ammunition was in fact degraded by tropical heat despite the degradation not being notable by simply looking at the powder and smelling it.
Intended working pressure of fresh ammo was more likely meant to be in the 43-45K CUP range.

The French ammo certainly showed some signs of poor manufacture and degradation as well.

That said the flurry of 7.62 NATO chambered rifles that suffered action failures at about the same time the Spanish 7.62 Mauser rifles began to be imported in quantity were caused by a very defective lot of Santa Barbra marked ammunition that when tested showed a percentage of those cartridges generated pressures of 67-68 K CUP, about the same as the US Army HPT High Pressure Test cartridge.
Another lot of defective 7.62 ammunition manufactured By CBC was also implicated in numerous action failures of rifles of various action types.

The M118 cartridge has a higher working pressure than what you see quoted in the ammunition technical manuals. Until recent years the propellant used for M118 Special ball was subject to increasing pressure in warm climates, up to 59,000 CUP in heated ammunition testing meant to mimic the heat inside an armored vehicle in desert conditions .
Recent developments in propellants have greatly reduced the sensitivity to heat.
The Propellant Procurement data sheets give pressures for the M118 in CUP only.
The Maximum Average Working Pressure of M-80 Ball is 48,000 CUP ( slightly less than the average for the German 7mm ammo tested) or 51,000 PSI. That's about the Max that I'd subject a 93-95 Mauser action to as a steady diet.

[Larry Gibson]

Multigunner

"That's about the Max that I'd subject a 93-95 Mauser action to as a steady diet."

Your calculated "steady diet" in CUPs is consistent with the 55 -62,000 psi measurement of various lots of U.S. M80 ball and M118SB I have measured which correlates to the conformal transducer psi's.

Not sure where you got the “48,000 CUP” for 7.62 NATO but according to your referenced NATO EVAT testing, the MAP of M80 Ball is actually 60,190 psi as taken in NATO designed EPVAT Barrel with a Kistler 6215 Transducer placed at the case mouth. That is NATO standard.It also falls in line with the pressure measurements I have taken over the last several years of numerous lots of U.S. M80 Ball and M118 SB.Just a couple days ago I tested 6 rounds of M118 SB LC-88; the MAP was 61,600 psi with a 5k psi ES.As I’ve said previously the measured psi’s of U.S. and other NATO spec M80 ball has given MAPs of 55,700 psi to 63,300 psi.The strain gauge measurement used by the Oehler M43 gives very comparable measurements to conformal peizo transducers.I also have “calibrated” the test rifle using “reference ammunition” as prescribed by SAAMI.

The strain gauge/peizo transducer psi measurements correspond to current methods of psi measurement of chamber pressures not the older CUP method of measurement. Older CUP measurements, or even current ones, do not give the same measurement of "psi".That is why older CUP measurements are now refered to as “CUPs”.Strain gauge measurements and peizo transducermeasurements are referred to as “psi’s”.Older references to CUP “psi’s” do correlate to strain gauge or peizo transducer "psi”.You can’t compare the two different methods by saying 50,000 CUPs is lower than 60,000 psi’s because in reality it isn't.However, using the .308W SAAMI MAPs of both CUP and transducer psi’s, you can say that 52,000 CUP is equivalent to 62,000psi (transducer) in the .308W cartridge (it may be, and probably will be, different in other cartridges of different calibers).

Also the velocity ES of the German 7x57 inthe Ordnance Report is 35 fps and the pressure variation is but 7,000 psi. That actually isn’t that bad and should not give any indication of deterioration.I can show you a recent test (10 shot) of Remington factory 150CL .308W that gave 88 fps velocity ES and a pressure ES of9,600 psi.Those ES of velocity and psi are still within what SAAMI calls “inclusion limits” for acceptable ammunition.

As to what “data sheets” (could you post the ones you reference or at least provide a reference source?) may say are changes made to M118SB I do not know. What I do know is I have been pressure testing numerous lots from the mid ‘80s to the late ‘90s and it all tests out pretty consistently in the 60 – 62,000 psi range.Now on the other hand M853 and M852 LR has gone through several powder changes based on who manufactured the specific lot.Powders were changed from older non- canister IMR4895 used in M118 white box (never was a NATO spec cartridge) to slightly slower burning powders such as IMR4064,Varget and RK15.That was done to enhance ballistic performance (velocity with accuracy) at longer ranges for use in M24 and M40 series sniper rifles.

Fact still remains, regardless of assumptions you, I or others have made based on information gleaned from “data sheets” or other quoted “sources” and any or all our comparisons of such the actual measured pressures of military ammunition made for use in Mauser SR actions runs from 51,000 to 60,000 psi.

Larry Gibson

[Multigunner]

"Not sure where you got the “48,000 CUP” for 7.62 NATO"

I told you, from the propellant procurement data sheets, and I said it was the max average working pressure for M80 Ball not each and every mark or bullet weight of 7.62 NATO ammunition.

7.62 NATO specifications for interchangeability of Infantry Ball required bullet weights of 144 to 150 grains with max working pressures of 48,000 CUP or 51,000 PSI.
The whole point of manufacturing the M118 Special Ball was to provide better long range performance than achieved with the standard M80 Ball. The difference would be akin to that of .30-06 M2 Ball (150 gr) vs M1 Ball (175 gr.), the M1 Ball being developed for better long range performance than the original 150 gr .30-06 WW1 era cartridge. The M118 was intended for MG and sniper use, with improvements to the newer M118 Long range cartridge intended mainly for sniper use.

Why your measurements exceed those of the US Army testing and those of the Cartridge and propellant manufacturers I have no idea other than possible degradation of propellants.

The Propellant procurement sheets were on an older PC that had a meltdown.
I found this shortcut that may be dead on an early thread on the general subject.

http://www.everyspec.com/MIL-SPECS/MIL+SPECS+(MIL-P)/download.php?spec=MIL-P-3984J(AMENDMENT3).008538.PDF

If I can find the PDF again I will post the information found there.
When stored 7.62 is tested after 15 years on the shelf any significant percentage of the test fired cartridges generating the pressure levels you describe would mandate the entire lot be sold off as surplus or scrapped for components.

[Multigunner]

This may be the proper PDF file

https://www.google.com/url?q=http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-P/download.php%3Fspec%3DMIL-P-3984J.008537.PDF&sa=U&ved=0ahUKEwje67jpzNnSAhVIxlQKHV8ND9g4ChAWCAgwAQ&client=internal-uds-cse&usg=AFQjCNE2dObMp7bXf1pV52C7FzXpa62yGQ

[Dutchman]

The cartridges show by LarryG in post #12 are/were quite excellent with superior accuracy as I purchased and shot some of those many years ago. Purchased from Southern Ohio Guns. Polvora Esferoida Belga- Belgian spherical powder.

For those who get tired or confused by all the arguing and the numbers and the blah blah blah there is only one issue you need to deal with. Very simple decision.

Throw caution to the wind.

or

Err on the side of caution.

You don't need to know anything beyond which path you'll take when the time comes.

When I put this page together, which by the way, is the most shared page at my website, it was with a sense of responsibility towards my fellow gun collectors and shooters and their families so you can't say you weren't warned.

http://dutchman.rebooty.com/1895Chile.html

Dutch

[Larry Gibson]

Multigunner

Why your measurements exceed those of the US Army testing and those of the Cartridge and propellant manufacturers I have no idea other than possible degradation of propellants.

There in is the problem.....my measurements do not "exceed those of the US Army testing and those of the Cartridge and propellant manufacturers"....they are essentially the same. It is you who misunderstands the difference between CUP pressure measurement and strain gauge/peizo transducer pressure measurement. I have attempted several times to explain the difference but you're just not getting it. I suggest you google SAAMI and compare their CUP MAPs to the Peizo transducer MAPs. You might also Google C.I.P. and compare the same.

Just compare the MAPs for the .308W. You will find the CUP MAP is 52,000. You will find the Peizo Transducer MAP is 62,000. It is as simple as that. Do you really believe that every lot of different cartridges I've tested has powder going bad?

BTW; where you ever got the idea M118 was "intended for MG and sniper use" leads me to believe you really have little idea what you're talking about. No offense intended but everything in this world can not be found on the internet. I suggest you do some serious research. Heck, even Wikipedia has it correct what M118 was developed for.....match shooting with the M14........btw; the military had no "snipers" when M118 was developed in the early '60s.........you might google Wikipedia on that........

Anyway, I'm through here. You really should google SAAMI to really see what the difference in psi measurement between CUP and transducers. Trying to compare apples vs oranges (CUP vs Transducer pressures) as you are simply makes my original point......that comparison is meaningless.

Larry Gibson

[texasnative46]

CHeatermk3,

I cannot tell you if any 1895 Mausers were ever in 7.65x53mm BUT several European sporter rifles WERE made produced with 1893 & 1895 actions in MUCH more powerful calibers & those sporters have held up to hunting since about 1910. = When I was stationed in USAREUR years ago, I saw a Forstmeister's rifle chambered in 10.75x62mm. - That rifle was built long before WWII, as the 1936 RWS catalog no longer listed that cartridge.

yours, tex

[CHeatermk3]

Interesting discussion re pressure and the different ways of measuring it. I originally asked because I had been considering purchasing an M95 Chileno on Gunbroker. I learned a few things I did not know as well as that somethings I thought I knew were not true.

I'm glad I didn't go after the rifle in question as there would have been no way of knowing ahead of the purchase(or even upon inspection after receipt) what the conversion to 7,62 did in fact entail.

[Larry Gibson]

CHeatermk3

That's probably a wise decision. I've passed on a couple three of those converted M95s over the years as with out a close visual inspection of the bore in front of the chamber ( a bore scope is perhaps necessary) it's almost impossible sometimes to tell if the rifle has a sleeved chamber. It's gas eroding or seeping between the chamber sleeve and barrel regardless of the chamber pressure that can have disastrous results. Not my cup of tea......now a nice M95 still in 7x57......but then that's what mine is......:D

Larry Gibson

[racepres]

And I thought that it was fairly easy to tell if it had a Chamber insert...
my conversion does not...Mine had the Barrel set back, which is Discernible visually, then bored and Chambered. But...[big Word] Mine is Not Chileano...it is a Spanish 1916!
Note that a 7x57 chamber will not clean-up going to 7.62 NATO, without setting the barrel back, or using an insert.. The Insert being the Cheap way I would assume..
Just an Informative
http://masterton.us/Unmarked1916
Link
if inappropriate mods please remove

[Multigunner]

"BTW; where you ever got the idea M118 was "intended for MG and sniper use"

M118 Match Cartridge was developed for competition, the M118 Special Ball and M118 Long Range which are the only M118 cartridges referenced in the data sheets I've mentioned were in fact intended for use by U S Army snipers. They were a development of the obsolete M118 Matchgrade ammunition. The cases and bullets and practically everything about them were different than those used for the M118 match grade ammunition which had by that time been superseded by the M852 Matchgrade competition cartridge.

Average working pressure of the M80 Ball is listed as 48,000 Cup or 51,000 PSI EPVAT. The Maximum deviation of the M80 Ball is 56,000 PSI EPVAT Any significant percentage of cartridges registering pressure higher than that would be grounds for condemning the lot tested.

The Data sheets I linked to give the pressures in CUP, but the later amended data sheets give the pressures in both CUP and PSI EPVAT.
If the method you are using gives readings dissimilar from the standard methods used by the U S Army Ordnance department take that up with them.

[Larry Gibson]

There's the exact point I was making; Multigunner apparently still believes I am saying Dutchman's quoted information is wrong, that the "data sheet" he quotes is wrong and now that the US Army Ordnance Department is wrong. I never said that at all. What I simply said was to compare CUP pressure measurements with transducer pressure measurements is wrong and obviously confusing. I stated the figures Dutchman quoted was "essentially correct". Multigunner apparently still has issues understanding the difference between pressure measurement via CUP and that of strain gauge/Transducer and the associated differences between the end measurements of each.

My pressure measurements are in accordance with those taken via a transducer. They will be higher than those taken, of the same ammunition, via a CUP measurement just as are the CUP and transducer measurements different as measured by SAAMI, C.I.P. and EVAT methods. What I am reporting is not the MAPs (Maximum Average Pressure) for the cartridges. I am reporting the actual pressures of various cartridges (military and commercial) of various calibers originally used in Mauser actions as tested in Mauser rifles, SR and LR models. If a M95 Mauser rifle is safe shooting 7x57 factory and military cartridges that generate 45 to 60,000 psi as actually measured then those actions should be safe with other cartridges (if a safe conversion was done) that generate the same 45 - 60,000 psi as actually measured. Again note that is with pressures actually measured, not taken from "data sheets".

I am also pointing out the erroneous assumptions that are made when comparisons of CUP pressure measurements are made with pressure measurements made by strain gauge of transducers. Apparently, unfortunately, Multigunner isn't quite understanding the difference and continues to make erroneous assumptions. He is not alone in making those erroneous assumptions.......:???:


I don't disagree with the CUP M80 pressure figures given in manuals, TMs, Ordnance Dept. reports and EVAT specifications. They are all essentially correct even though they do differ sometimes. As an example of different information here is a page from TM9-1305-200, Departments of the Army and Air Force and approved by the Army and Air Force Chiefs of Staff. Note; the pressures listed for M59 and M80 Ball are measured by CUP

190708

My experience with M118 has to do with having shot a lot of it over the years for practice, in competition, in training (as an SF Weapons NCO we trained as "snipers" with various sniper rifles such as M21s, M24s, M25s and various 50 cals bolt guns). I've shot a lot of the original XM118, M118 White Box, M118 SB and M118LR. I've also shot a lot of M852. I've measured the psi of numerous lots of M118, M118 SB and M852 along with a couple lots of M118LR. Pressure figures I post are not taken from "data sheets" but from actual pressure measurement of the ammunition. As mentioned earlier it is erroneous to believe all such ammunitions are load to the MAP, they are not.

In post # Multigunner states; " The M118 was intended for MG and sniper use, with improvements to the newer M118 Long range cartridge intended mainly for sniper use." I'm still wondering where he got the idea that M118 was ever intended for "MG and sniper use". It was, in fact, never intended for MG use, as it was always issued in 20 round cardboard boxes. Actually XM118 and M118 was developed for match use. During the Vietnam war and later M118 White Box was also the "standard" sniper cartridge for use in M21s and Marine M40s. Neither M118 White Box or M118 SB was ever issued in linked form for use in MGs. M118 SB was an interim cartridge intended for training using M21s, M24s and M40s. Over the mid '80s to early '90s it was gradually phased out as M852 replaced it. Soon, however, it was found M852 did not hold accuracy much beyond 800 meters as the bullet would usually lose accuracy do to it going subsonic between 800 and 900 meters. This led to the development of M118LR in the late '90s. As a mater of fact M118 White Box was not NATO spec 7.72 ammunition. Look on the head of any M118 White Box and you will not find the NATO designation (a 0 with a + in it) stamped on it. You will only find LC, the year and MATCH. M118 SB is made to NATO spec and will have the NATO spec designation in the head stamp also. I'm not reporting this information as gleaned from internet sites, I'm reporting it from personal experience with all the types of M118 from the late '60s to the present because as Elmer Keith said; "Hell, I was there...."

Bottom line is; it is erroneous to compare 7.62 NATO/.308W CUP pressure measurements with transducer pressure measurements unless you understand the difference. I also concur with Dutchman's advise not to shoot any 7.62 NATO or .308W cartridges in converted M95 Chilean rifles with the sleeved chambers.

Larry Gibson

[Multigunner]

" Multigunner apparently still has issues understanding the difference between pressure measurement via CUP and that of strain gauge/Transducer and the associated differences between the end measurements of each. "

I was quoting both CUP and Epvat transducer figures as published by the U S Army in the amended reference works I mentioned.
Nowhere have I confused the two. The working pressure of M80 Ball is 48,000 CUP or 51,000 PSI EVPAT. The M118 cartridge in all its incarnations from matchgrade to dedicated sniper cartridge exceeds that pressure significantly.

From Wiki
"EPVAT is an abbreviation for "Electronic Pressure Velocity and Action Time". With Action Time the (short amount of) time required between the ignition of the primer and the projectile leaving the barrel is meant. This is a comprehensive procedure for testing ammunition using state-of-the-art instruments and computers. The procedure itself is described in NATO document AC/225 (Com. III/SC.1)D/200."

When discussing the maximum allowable pressures for a milspec cartridge I'll stick to the methods actually used by our ordnance department.

As mentioned earlier the earliest comprehensive testing of 7X57 Ball ammunition I could find was that in the report of the Chief of Ordnance of 1898 and they used Copper Units of Pressure at that time.
The only variable would be the position of the crusher gauge piston along the cartridge case or case mouth. Old British descriptions of the method when used by British cartridge companies of that time frame gave the position of the piston of the radial pressure gun about 1/3 the way up the case body.

It would be nice if I could find that particular work again as it explained the process in detail and I'm sure it predated the Ordnance report.

[Multigunner]

" Multigunner apparently still has issues understanding the difference between pressure measurement via CUP and that of strain gauge/Transducer and the associated differences between the end measurements of each. "

I was quoting both CUP and Epvat transducer figures as published by the U S Army in the amended reference works I mentioned.
Nowhere have I confused the two. The working pressure of M80 Ball is 48,000 CUP or 51,000 PSI EVPAT. The M118 cartridge in all its incarnations from matchgrade to dedicated sniper cartridge exceeds that pressure significantly.

From Wiki
"EPVAT is an abbreviation for "Electronic Pressure Velocity and Action Time". With Action Time the (short amount of) time required between the ignition of the primer and the projectile leaving the barrel is meant. This is a comprehensive procedure for testing ammunition using state-of-the-art instruments and computers. The procedure itself is described in NATO document AC/225 (Com. III/SC.1)D/200."

When discussing the maximum allowable pressures for a milspec cartridge I'll stick to the methods actually used by our ordnance department.

As mentioned earlier the earliest comprehensive testing of 7X57 Ball ammunition I could find was that in the report of the Chief of Ordnance of 1898 and they used Copper Units of Pressure at that time.
The only variable would be the position of the crusher gauge piston along the cartridge case or case mouth. Old British descriptions of the method when used by British cartridge companies of that time frame gave the position of the piston of the radial pressure gun about 1/3 the way up the case body.

It would be nice if I could find that particular work again as it explained the process in detail and I'm sure it predated the Ordnance report.

If you are going to compare pressures of 19th century cartridges that are stated in copper units of pressure to a modern cartridge then its best to compare them only to pressures of that modern cartridge as stated in Copper Units of Pressure.

The extreme variation in pressures of the French and German ball cartridges with no corresponding increase in velocity at the higher pressures tells me that the powder used in those cartridges was either of low quality or degraded. The increases in chamber pressure were due to the powder not being consistent in efficiency. This was a recognized problem with the German Leaf powders when stored in tropical environments.

[Multigunner]

Double post, can't edit or delete

[Multigunner]

Try this PDF
Its easier to read and a more recent edition.
http://everyspec.com/MIL-SPECS/MIL-SPECS-MIL-P/download.php?spec=MIL-P-3984J_AMENDMENT-2.044248.pdf

I think theres also an Amendment 3 version.

[Multigunner]

Just remembered I have a reprint of the Mauser catalog for the 1893 rifle and its ammunition.

The "Gas Pressure" is stated to be 3100-3300 Kg, by which I believe they mean Kilograms per Square Centimeter.

3100 Kg would then convert to 44,092 PSI

3300 Kg would equal 46,937 PSI , no doubt in my mind as measured in Copper Units of Pressure.

So if my presumption of the method used is correct the 1893 rifle was designed to use ammunition that generated at most 46,937 CUP. Ammunition generating more than that figure would almost certainly be considered out of specification so far as the manufacturer of the rifles was concerned.

Notice I said nothing about transducers, they didn't use them back then anymore than they used strain gauges. The question has been what pressure level the rifles were designed to handle, not how hot they might load the same cartridge for use in more modern weapons.

[Larry Gibson]

Multigunner

I don't think you're understanding what you're reading in the PDF. Refer to page 3 of the PDF file (note; the PDF file is not the complete document. Much is left out, specifically the test standards and equipment used. Not being able to read the fine print can lead to erroneous conclusions) . That is the Ballistic Requirements for Propellants. That is not the NATO MAP for 7.62 cartridges. What theat PDF did was set guidelines for the loading of the cartridges. Note under "7.62" there are 2 lines for M80 ball. The 1st line is standard requirements for the M80 cartridge to be loaded to 2750 fps at 78 ft. (that also is the standard in the TM I posted earlier). That is the ballistic standard for the cartridge. The MAP, when loaded to that velocity, should then not exceed 48,000 CUP with a SD of 53,000 CUP under normal test temperature. It should not exceed 55,000 CUP under "extreme temperature".

Now note the next line shown with EPVAT (the NATO Standard) next to it. When loaded to 2765 fps at the same 78 feet at normal test temperatures the pressure should not exceed 50,940 CUP with an SD max of 56,016 CUP. So which is it 48,000 CUP or 51,000 CUP for M80? Note also the M118 LR is at 52,000 CUP. So for 7.62 NATO ammunition using your own spec sheet we see 3 very different CUP pressure measurements.....so which is it?

Also note next to each CUP measurement is a "4" there is an explanation what that means.....do you know what that explanation is? Next to the SD CUP measurement is a "13". The is "“13/ Case Mouth Pressure plus three (3) standard deviations as measured in the M230 test barrel (Dwg 9390748).” Are you aware what that means?

Can you tell us what the SAAMI and C.I.P. CUP MAPs are for the .308W? Can you also tell us what the transducer MAPs are for the .308W.

How about an example of different ways to measure the same thing. Take a 150 gr M1906 30-06 bullet and measure the diameter with a caliper calibrated in inches (why? Because that's how we measured it back then.) What is the diameter? Now measure the diameter of the same bullet with a caliper calibrated in metrics (why? Because that's how most of the scientific world measures bullets now). What is the diameter? Ok, let's keep it simple and say the inch calibrated caliber measured the bullet at .308". Then let's say the metric caliber measured the same bullet at 7.62mm. So which measurement is right? They both are.

Remember Dutchman used the transducer psi for the .308W and the CUP psi for the 7.62 NATO. So which was right? Both were. They were just different ways of measuring the same thing is all. That is why the comparison between the two is not valid.....they both are different.

BTW; The SAAMI CUP MAP for the 7x57 is 46,000 and the C.I.P. (from the European proof house) CUP MAP is 49,000. Which is right? The SAAMI transducer MAP is 51,000 psi and the C.I.P. transducer MAP is 57,000 psi. Which is right? Interestingly most all the 7x57 milsurp I have tested has been less than or very close to the C.I.P. MAP of 57,000 psi. You might also be interested to know the MAP of older Remington and Winchester factory 175 gr loads exceeded the SAAMI MAP by several thousand psi's (there was no SAAMI back when those were produced. Current Remington and Winchester 175 gr factory loads do adhere to the SAAMI MAP. And no, the powder was not deteriorated in any of the ammunition tested.

Larry Gibson

[Multigunner]

"Now note the next line shown with EPVAT (the NATO Standard) next to it. When loaded to 2765 fps at the same 78 feet at normal test temperatures the pressure should not exceed 50,940 CUP with an SD max of 56,016 CUP. So which is it 48,000 CUP or 51,000 CUP for M80? "

EPVAT does not use a crusher gun, EPVAT pressures are in PSI by transducer. You are misreading the meaning of the column header.
Also you didn't seem to notice the +/- 15 FPS.

As I mentioned there's a third Amendment to this paper. When I find it again I'm sure that will make everything more clear. that's the purpose of the amendments.

" Which is right? Interestingly most all the 7x57 milsurp I have tested has been less than or very close to the C.I.P. MAP of 57,000 psi"
And how close would they be to the factory specs of 3100-3300 Kilograms per square Centimeter.

I believe I mentioned earlier how 93-95 actioned Mausers failed during the gran Chaco War when post WW2 milspec ammunition that was simply too hot for the older actions was used.
Why don't you dig up some of that vintage DWM 7mm loaded to drive a 154 gr bullet to 2900+ FPS and let us know what your stain gauge has to say about that.

[Larry Gibson]

"Why don't you dig up some of that vintage DWM 7mm loaded to drive a 154 gr bullet to 2900+ FPS and let us know what your stain gauge has to say about that."

Easy enough. The DWM, PS 50 and PS 51 (Spanish made) 7x57 were both loaded with 154 gr FMJBT bullets over 39 gr of the atypical European square cut pieces of flake powder in Berdan primed cases. The DWM had a lacquer sealant around the case mouth. Examination of the powder from several cartridges of each found no evidence of powder deterioration. The measured MAP out of my test rifle (Chilean M95 in excellent condition) using the M43 Oehler PBL for 10 shot test strings gave 57,300 psi for the DWM and 57,900 psi for the PS 51. The PS 50 gave the highest MAP at 59,400 psi. Some Spanish made 1918 with 172 gr cupro nickeled bullets gave 54,500 psi.

BTW; here is the U.S. Army's specification sheet for the M80 cartridge right out of TM 43-0001-27. The psi measurement is in CUPs and is 50,000 not 48,000. What Dutchman quoted was, just as I've said, essentially correct.

190747

Larry Gibson

[Larry Gibson]

The information I've researched has the pressure measured in Europe back then during the development of the Mauser SR actions and the cartridges, including in Germany, as using the "bar" unit of measure. The figures were reported for the 7x57 in the development of the cartridge were for a MAP of 3900 "bar". That converts (1 bar = 14.5 psi) to 56,550 psi......? The 7.65 Argentine had the same bar MAP. The 6.5 Swede was 3800 bar (55,100 psi).

And as I told you earlier EVPAT using a conformal transducer at the case mouth which give slightly less pressure than when measured a mid case body. Perhaps that accounts for the slightly lessor "peizo" measurement on your data sheets.

Have you looked at the SAAMI and C.I.P. MAPs both CUP and transducer to actually see what the difference is?

Larry Gibson

[Tackleberry41]

I have seen this 'discussion' over and over in various forums. Place near me had a converted Spanish mauser. So I asked about it not being that knowledgeable about such things. About half said it was junk, period, that a box of store bought 308 was asking for a trip to the hospital. I have yet to eat a bolt. Havent even tried to run store bought thru it. Only store bought I have is 20rd boxes of surplus for my CETME. Im not one to load to max to begin with. Its been digesting a diet of min to med 308 loads, with nary a hiccup.

A quick look at wikipedia, some claim the info they put up is junk, maybe on the controversial or political stuff. But why would they screw with '7x57 mauser'? Factory 7x57 is listed as 51,000psi SAAMI or 56,565 C.I.P., not sure why suddenly 308 has to be kept to 46,000psi.

Wikipedia does have this, which gives several testing methods to further confuse things.
https://en.wikipedia.org/wiki/Small_arms_ammunition_pressure_testing

[Multigunner]

"BTW; here is the U.S. Army's specification sheet for the M80 cartridge right out of TM 43-0001-27"

Notice the cartridge drawing on that page is of a .30-06 cartridge.
I mentioned earlier that those manuals are full of such errors, which is why you should go to the source material , the propellant procurement data.

" The psi measurement is in CUPs and is 50,000 not 48,000."
I see nothing there about CUP.
The entry gives a ball park figure, which is why much of the information in that manual is suspect.

[Multigunner]

"A quick look at wikipedia, some claim the info they put up is junk, maybe on the controversial or political stuff. But why would they screw with '7x57 mauser'?"

If you look at the comment they made about the average working pressure being over 50 CUP using the very same Ordnance dept testing of captured 7mm ammunition they choose to use only the figures given for the obviously defective or degraded (split case necks for one obvious sign) French manufactured ammunition which greatly exceeded that of the German manufactured ammunition which itself showed obvious extreme variations in chamber pressure without corresponding increases in velocity. The German ammo, even with its extreme variations gave a average pressure of 48,600 CUP.

Gibson
"The information I've researched has the pressure measured in Europe back then during the development of the Mauser SR actions and the cartridges, including in Germany, as using the "bar" unit of measure. "
German proof test pressures in the 19th century were in Metric Atmospheres which is the equivalent of BAR, but they did not use transducers because they did not have them to use.
Any comparisions made would be apples and oranges.

[Larry Gibson]

Multigunner

I stated earlier that the 7,000 psi ES along with the 35 fps ES of the 10 shot test of the German 7x57 ammunition conducted in 1898 was well within the allowable ES variations of SAAMI, C.I.P. and military standards of today (our military ammunition testing conforms to SAAMI specifications). There was absolutely nothing about the German ammunition "which itself showed obvious extreme variations in chamber pressure without corresponding increases in velocity" that is out of the ordinary for many, many acceptable tests of commercial and military ammunition.

You really should look at the SAAMI manual on their standards instead of relying on internet searches for misinterpreted information. Try going to the horses mouth for the straight information. None the less lets try this as one last stab at helping you understand:


SAAMI CUP MAP for the 7x57: 46,000 CUP
C.I.P. CUP MAP for the 7x57 : 49,000 CUP

SAAMI transducer psi for the 7x57: 51,000 psi
C.I.P. transducer psi for the 7x57: 57,000 psi

The Ordnance Departments CUP measurement in 1898 of the German 7x57: 48,600. Last time I checked Germany was still in Europe in 1898 and would have to be adhering to European stands i.e. the C.I.P. MAP of 49,000 CUP. Obviously the German ammunition was within that standard.

Now if the C.I.P. CUP MAP is 49,000 and the C.I.P. transducer MAP is 57,000 won't they be one and the same even though measured by different means? If the SAAMI CUP MAP is 46,000 and the SAAMI transducer MAP is 51,000 won't they be one and the same even though measured by different means? That being the case then my measurements of factory 7.57 ammunition and milsurp 7x57 ammunition as taken with the strain gauge are entirely in line with both SAAMI and C.I.P. transducer measurements.

Larry Gibson

[Multigunner]

"The Ordnance Departments CUP measurement in 1898 of the German 7x57: 48,600. "
Which is still a long way from the 50,000+ CUP claimed in the Wiki entry and higher than the working pressure found in the Mauser Oberndorf catalog.

Look at the velocities of each round fired then compare the chamber pressures of those rounds. The powder was degraded, not to any great extent but degraded just the same by storage in a tropical environment which Cuba certainly is.

The German 7mm tested was within reasonable limits but not to design specifications. The French ammunition the Wiki entry used as a basis for their claim most certainly showed shoddy workmanship and exceeded the pressures of the German cartridge.

Average pressure is an average, not the highest or lowest of cartridges tested.

"(our military ammunition testing conforms to SAAMI specifications)" not sure what you mean by conforms through apparently M118 LR is tested along the lines used by SAAMI. The M80 Ball is tested by EPVAT methodology and by the radial crusher gun. The CUP readings may be the same but the transducer methods are not, in part due to the necessity of establishing gas port pressures.

[RoyEllis]

dam...now I've got a headache. I recall how my first wife would argue with a potato peel if she took a notion.........

[Larry Gibson]

Multigunner

It is painfully obvious you've little or no experience measuring the pressure of any cartridge. It is also painfully obvious you've not bothered to read the SAAMI standards or really read the Wikipedia reports on the EVPAT pressure measuring. Our Ordnance Depart adheres to the testing standards and procedures of SAAMI. That includes CUP pressure measurement and transducer pressure measurement on the case body and at the case mouth. If you had read the SAAMI standards you would know it is for commercial manufacturers of which most of our military small arms ammunition are made by. You would also have found there is no SAAMI specification for the 7.62 NATO cartridges because those standards are under STANAG agreements.

I have measured the internal ballistics of literally thousands of test round of 35+ cartridges. A measured MAP and a MAP standard SAAMI, C.I.P. or EVPAT are most often different. The standard MAP is what loaded cartridges should not exceed under standard test conditions. The measured MAP of any lot of ammunition is often different and often lower than the standard MAP. Once again, cartridges are loaded to a specific for the cartridge velocity +/- not to exceed the standard MAP. That does no mean they are loaded to the pressure level of the standard MAP. Had you read the SAAMI standards you would perhaps have understood.

The fact that the German 7x57 ammunition tested in 1898 averaged 48,400 CUP and the Wikipedia MAP for the 7x57 says its 50,000 CUP is as it should be.

A pressure variation of 7,000 psi ( the ES of the 10 round test string in 1898) is not bad at all and is absolutely no indication of powder degradation. Especially since the Ordnance experts who examined it found none. How you, 119 years later, without any personal examination of such can determine the powder was degrading based on what you assume to be an extreme ES of pressure is a stretch even for the internet. The ES of 7,000 CUP for a 10 round test string is quite acceptable especially considering the ES for the velocity was only 35 fps. All in all quite good even by todays acceptance standards. The German ammunition was well within "design specifications". No it was not loaded to the standard do not exceed MAP but then most lots of ammunition loaded then and loaded now are not either. Your error apparently is thinking all ammunition is loaded to the MAP for the cartridge.

I am assuming also you mistakenly believe that in a test of the same ammunition that a slightly higher pressure always results in a higher velocity? That is not so as I have seen the reverse many times. I also have seen, many times in the same test string, psi's of 1000+ variation with but 3 - 5 fps difference. Should you actually delve into any actual pressure test results to SAAMI, C.I.P. or EVPAT standards you would see that. You could also ask any ballistician. They have all seen the variances too. Stating that such variations is caused by degradation of the powder belies your inexperience in such test matters.

"(our military ammunition testing conforms to SAAMI specifications)" not sure what you mean by conforms through apparently M118 LR is tested along the lines used by SAAMI. The M80 Ball is tested by EPVAT methodology and by the radial crusher gun. The CUP readings may be the same but the transducer methods are not, in part due to the necessity of establishing gas port pressures."

Yes, our M80 conforms to the STANAG specifications using EVPAT testing criteria. So who do you think produces our M80 ammunition? It is commercial manufacturers as we have not had government own small arms manufacturing for some years. Those commercial manufacturers use SAAMI test specifications conforming to the STANAG 7.62 NATO criteria of which EVPAT is a part. Where do you think SAAMI developed the test criteria, standards and specifications from? Take a hard look at that test conducted in 1898 and you'll see the beginnings.

At any rate, you obviously refuse to consider other than you've gleaned and obviously misinterpreted off the internet. I've tried over and over to show you where to find the correct information. I've led you to the trough, it is up to you to drink or not. Have a good night.

Larry Gibson

[Multigunner]

"The fact that the German 7x57 ammunition tested in 1898 averaged 48,400 CUP and the Wikipedia MAP for the 7x57 says its 50,000 CUP is as it should be. "
Did you bother to read their reasoning for making that claim? They based it not on the average pressure of 48,000 CUP of the German ammunition but rather on the higher pressures generated by whatever off brand French ammunition was tested along side it. Did you bother to find and read the Mauser catalog entry on the Spanish Mauser and its ammunition. I've had my reprint which was published in Gun Digest in 1961 since I bought my second Mauser. The specifications for the 7mm are very complete and contributed by DWM.

The Wikipedia claim of 50K CUP then exceeds the design pressure envelope of the 7mm Ball cartridge as manufactured specifically for the rifle when it first came out and the pressures generated in testing.
The Mausers were proof tested at a higher pressure in order to take into account the known effects of degradation of powders stored in Tropical Climes. From reference works of that time period the Proof Testing of Military smokeless powder rifles were done using the Special Leaf powder which was a form of the standard "Leaf" or flake powder formulated to generate higher pressures at the same charge weight.

The question was not how far out of spec off brand 7mm cartridges can get before the rifle is damaged, it was what pressure level the 93-95 actioned rifle was designed to digest.

As the condition of many of the converted rifles and some still in the original chambering suggests a diet of cartridges that generate pressures beyond that of the designed specification does in fact damage the rifle though it may take many rounds fired before the damage becomes obvious.

Its also obvious that that there are very good reasons why cartridges in storage are tested at intervals by lots and when any significant percentage exceed the stated maximum pressures the whole lot is condemned.

If SAAMI and EPVAT testing are the same tell us what the gas port pressure standards for the 7.62 , the .308 or any other cartridge is going by SAAMI specifications. That should be easy enough.

[Tackleberry41]

Larry your wasting your time. Its alot of typing for no results, one would think this was the pit.

[Larry Gibson]

Tackleberry41

You are absolutely correct, I'm not wasting any more time.....Multigunner just wants to argue, I'm moving on.

Larry Gibson

[Scharfschuetze]

Yep, probably best to put this one to bed.

My take on the original topic of small ring Mausers is that maturing designs (91, 93 & 95) don't improve with age and steel doesn't get stronger with age. Having seen older Mausers with lug set back, I'd be inclined (if I had a 95) to just load it down and enjoy it. I do that with my SR Argentine Model 91 Mausers and enjoy them immensely.

Lots of good info in the thread though. I appreciate that.

[Larry Gibson]

Scharfschuetze

Couldn't agree with you more. The jacketed loads I use in my own SR Mausers of various original cartridges I keep at or below the C.I.P. MAPs and mostly below or at the SAAMI MAPs. Doing that has nothing to do with what the original loadings of the cartridges actually were. Those I've found are most often just +/- the C.I.P. MAPs. In post #15,http://castboolits.gunloads.com/showthread.php?330190-Handloading-for-a-1916-Spanish-Mauser-7x57 I list several of my favorite 7x57 loads I use with jacketed bullets in my M95 and other M93s and M1916s that have come through my hands. I've become especially fond of that listed 175 RN load, amazingly accurate and, I'm sure, would be quite deadly on game.

Larry Gibson

[racepres]

Scharfschuetze (http://castboolits.gunloads.com/member.php?23645-Scharfschuetze)
Well Said!!
While I have One 7X57 that is Not a SR Mauser...I shoot it very Little..My '93 gets a Serious Workout...Tho my '95 is More accurate...
I do Not Custom Tailor loads...I load "By the Book" Cast Boolit loads, and Enjoy immensely.

BTW I have yet to load any 7X57 with a Boolit/J-Word, heavier than 140 gr!!!!!!
Flame On!!!!!!!!


Darn!!! Edit to get on Subject...my CETME 1916 [308] has digested a gajillion 150gr Boolits with 12 gr of Unique under them...Hasn't missed the Swinging target, nor Stray Critter...yet...Scout scope HomeMade mounted quite a few years ago...
http://www.amraonline.com/Gunpics/1916.jpg

[Larry Gibson]

Here's my Oveido M1916 (Made in '28) I built back in '68. I got just the complete action for $8. Put it into a Richards Micro-Fit stock and put a Star 26" sporter barrel on it chambered in .308W. You can see the stock is cut out where I had put a Lyman 48 Long Slide receiver sight. I made a front sight base for an M14 front sight. It has a Dayton/Traiser trigger and was converted to cock on opening. I shot that first Star Barrel out and put another one on it also chambered in .308W. Shot over 10,000+ rounds of US M80 Ball and along with one can of XM118 and a couple cans of M118 through those two barrels along with some hellacious .308W handloads (were max loads in older manuals) which proved out to have mid 60,000 psi's. That rifle has accounted for numerous deer, a couple elk, who knows how many coyotes, untold number of rock chucks and jack rabbits.

After the second barrel was shot out in the late '70s I pulled the barrel and found minimal lug set back of .001 - .002" maybe. I had a new two groove 'A3 barrel and had it set back and rechambered to a cast bullet cartridge of my own design; the .308 CBC. That's what it is today.

190890

Here's the M95 Chilean 7x5 I use for pressure testing.

190891

Larry Gibson

[CHeatermk3]

Wondering now how to "clean up" the bit of frosting evident in my Chileno's barrel--I cleaned and cleaned it and the cleaner it (bore) got the worse I looked! By the time patches quit coming out blue/green, they were coming out clean but kinda roughed-up--the bore felt kind of "grabby", so I thought I'd try shooting some jacketed thru it and clean it up after every few rounds.

Accordingly I bought a few hundred 174 gn Privi FMJBT bullets from Powder valley--Loaded up 50 and shot them over 41.2 gns of AA2700 and went back to cleaning with Wipe-out foaming cleanser. Seems to be working out; how much of this do you think I'll need to do to get to the point I can shoot boolits without too much leading? The I've gone up to 42.5 gns of 2700 and plan on cleaning after every 10 rounds--fired 5/cleaned yesterday and the bore is starting to look kinda shiney.

Do you think 42.5 gns is too much? Primers look OK but I don't want to abuse the old girl; I planned to shoot only boolits but the grabby bore condition made me think twice about that!

[Multigunner]

I've heard of a condition called a "hairy bore" where thermal alligator cracking of the surface turns up at the edges like dried mud flats. Fibers from patches catch on the rough edges leaving a fuzzy hairy look when you look down the bore. Its mainly found in very old milsurp rifles that have fired thousands of rounds of cartridges loaded with high nitro content double base powders. More modern barrel steels aren't as affected by this thermal cracking. Some modern barrels are nitrided in manufacture to head off the situation before it starts.
I only remembered it because the first time I heard of it was in relation to old Boer War Mausers.
I've seen this a few times in the past but didn't know what caused it till a few years back.

If it is thermal alligator cracking the bore surface will be many times harder than whats underneath and brittle, sooner or later the brittle scales break away.
Hardened carbon fouling infiltrating the edges of the scales is what turns the edges up and to some extent stabilizes the surface.
You'll probably have to have the bore lead lapped to get rid of it, and that may not work, and if it did the bore would be enlarged.
Fire lapping might work, probably worth a try.

Anyway that's the only thing that comes immediately to mind, it may be something else entirely.

[racepres]

My one Large ring Mauser 7mm barrel is about a sewer pipe...but..better than it was when I first got it. I did shoot a 1916 7mm clean[er] it came around pretty good..and now gets only cast [oversize]. I am thinking I will try Paper patched smokeless loads in the '98...see if it shoots clean.

[Larry Gibson]

My one Large ring Mauser 7mm barrel is about a sewer pipe...but..better than it was when I first got it. I did shoot a 1916 7mm clean[er] it came around pretty good..and now gets only cast [oversize]. I am thinking I will try Paper patched smokeless loads in the '98...see if it shoots clean.

Might try fire lapping with cast that fit the barrel. I have smoothed out several milsurp barrels that still had strong rifling. They all shot fairly well with cast afterward. I have the old fire lap kit that is now sold by Wheeler(?). some grits of valve grinding compound can also be used successfully. Easy to do.

Larry Gibson

[racepres]

Might try fire lapping with cast that fit the barrel. I have smoothed out several milsurp barrels that still had strong rifling. They all shot fairly well with cast afterward. I have the old fire lap kit that is now sold by Wheeler(?). some grits of valve grinding compound can also be used successfully. Easy to do.

Larry Gibson

yes I know about that...even have done it..Handlapped as well..This time, I wish to try the Paper patched in order to satisfy my curiosity. Paper patched barrels sure look ...Shiney!!!
and I don't think the dimensions are changed to extent that Firelapping changes the throat. But
IDK

[JHeath]

I'm always glad to see Larry pipe up and when a certain Swede Mauser expert joins, it's like getting to watch Ali vs. Foreman again. I build rigging systems. Many components are marked with a "safe working load." This might be based on a design factor of 4 or 6 or whatever. Other components are sold with a "minimum breaking strength" and the user applies his own design factor. The pressure of 7x57 military ammo is only half the information. What is the failure strength of the action? If the action fails at 110,000lbs, and Larry is willing to run it at a design factor of 2 (55k vs 110k), but Multigunner insists on limiting it to 45k, the difference is really about design factor. Not pressure. And this is exactly like the donnybrook over low number 03s. Somebody asked about shooting 25k cast loads in 03s. People screamed because some of those rifles fail at 80k when they were *supposed* to fail at 125k. But the guy who runs them at 25k has a design factor of 3. Those who run full-house 60k loads through a double-heat-treated late 03 have a design factor of only 2. With the 95, knowing the ammo pressure only tells you the "official" safe working load. It does not tell you the design factor. A Hilti concrete anchor is sold with a DF of 4. A Crosby shackle is sold with a DF of 6. If I my spec requires a DF of 10, I can use those components by doing the math and oversizing them. If my spec allows a DF of 3, I can exceed the factory-rated safe working loads of those components. Wire rope has no listed safe working load, only breaking strength. That 95 action is not stamped with a safe working load. What is its breaking strength, and what is the required design factor? That's all that matters.

[Multigunner]

Metal fatigue is cumulative. If subjected to hundreds of rounds of ammunition that exceeds design specification the gun doesn't have to show obvious signs in order to have received irreparable damage that may result in a catastrophic failure at some future date.

If a rifle is designed for a specific working pressure considered safe and overbuilt enough to withstand a number of firings with out of specification ammunition not exceeding the proof test pressure but is then subjected to a steady diet of out of specification ammunition then metal fatigue will take its toll.
From what I have read on the subject of German proof testing of the Gew 88 they used a powder formulated to mimic powder degraded by years of storage under tropical conditions.
If a cartridge designed to generate 46,000 CUP was expected to generate 58,000 CUP after years of degradation then what pressure might one expect from a cartridge designed to generate 50,000 + CUP after being subjected to the same sort of degradation.

Lug setback is an obvious sign of ammunition exceeding the design specification. Micro fractures that once started by a few too many rounds of ammunition that exceed the design specs will continue to grow at every firing no matter what the pressure of later rounds is a sign the shooter has no way of knowing about.

I recently found photo copies from a re barreling shop manual given to me many years ago. These pages deal with re barreling military Mauser actions and inspection of candidates for re barreling. The entries on actions found far too degraded to be safe to re barrel are interesting.

[JHeath]

No. The CIP pressure for 6.5x50 Japanese is 43k. The CIP pressure for 6.5x54 Mannlicher-Schoenauer is 53k. Can you rechamber an Arisaka to 6.5x54 M-S? It exceeds the spec for the original chambering. Does that make it unsafe? No. Whether it's safe or not depends entirely on the ultimate strength of the action. It's got zero to do with ammo specs. If you buy a 7x57 Ruger No. 1, you can rebarrel it to .308. I can rebarrel my FN/Venezuelan 7x57 98 to .308. Whether it's a good idea for a 95 depends on the safety margins of that action. You cannot assume that 7x57 ammo pressures have a certain relationship to the action strength. You have to know the action strength.

[Multigunner]

"You have to know the action strength"
I think the numbers of 1893 actioned Mausers in 7.62 found with lug setback gives a good indication of the ultimate strength of the action compared to other action types also barreled or rebarreled to 7.62.

Metallurgy was fairly advanced in the late 19th century, but as working pressures of cartridges climbed new alloying agents and heat treatment methods were sought and developed precisely because confidence in the older actions to handle ammunition that gave better performance was waning. Between wars some nations imported higher quality proprietary steels to manufacture their own rifles precisely because the steel they normally used was no longer up to the task.

Factory specifications for the 7X57 ball cartridge were set at 3100-3300 Kilograms per square centimeter as the best level to allow good performance while not over stressing the action. They could have loaded the cartridge much hotter if they wished, but to do so would shorten the arm's service life and increase problems of excessive pressure of degraded ammunition, which every user of smokeless propellants had recognized as something not to be ignored.

The ultimate strength of the action when new and freshly proofed is not going to be the same as that of the same action after it has been subjected to thousands of rounds of ammunition that generates excessive pressures.

The early Mausers are an example of cartridges and rifles developed side by side. The 1998 Mauser action is an example of improvements in the basic design to take into account the higher operating pressures of more modern higher velocity ammunition types. Even now the WW1 era 7.92 cartridge is as powerful and efficient as the 7.62 M80 ball cartridge if not more so and the 7.92 heavy ball of WW2 is in the same ball park as the hotter M118.

I stated that the 48,000 CUP design pressure of the M80 ball is about as much as I'd subject a 93-95 action to. As the ordnance report made plain enough the German manufactured 7mm ball averaged the same 48,000 CUP, which you could round up to 49K if you wished to. Despite what I consider a wide range of pressure among the samples, from 43,000 to over 50,000 only a few of the sample cartridges exceeded the average pressure which itself exceeded the design pressure envelope a bit most likely due to storage conditions.
The pressures of the shoddy French manufactured ammo tested along side the German ammunition would be a worst case scenario, evidence of the rifles having a reasonable margin for error that was being pushed. I would not have wanted to use the French ammunition any more than the homegrown Boer Kortnek ammo which was known to cause catastrophic failures of new or nearly new 93 Mausers.

If one wished to take a converted Spanish Mauser in overall good condition and use hot 7.62 or .308 factory loads with the intention of only using the rifle occasionally and retiring it once the headspace increased beyond recognized safe limits that's up to them.
I don't doubt that many of the Spanish 7.62 rifles were sold off precisely because they showed signs of increased headspace while in service, they were certainly not intended as a main battle rifle at that time anyway. Once the actions suffered lug setback they were not worth further work since the receiver was to all intents and purposes shot. If not palmed off on the surplus market they'd have simply been scrapped.

[Tackleberry41]

Here we go again.

[Larry Gibson]

Here we go again.

Yup, some just can't get it through their head that the design specification for a cartridge and the design specification for an action are two different specifications. I also wonder if they comprehend the actual quality difference between various manufacturers of the SR Mauser actions. There is a considerable difference between German made M93s, M95s, and German and Swedish M96s compared to the various Spanish made M93 actions. Perhaps the best of the Spanish made actions was the Oviedo's. The earlier post of mine showed the 1928 Oveido M1916 that, besides who knows how many 7x57 barrels it went through, was used to shoot out 2 new .308W barrels with 10,000+ US M80 ball rounds plus probably several thousand .308W reloads that were found to be generating 64,000+ psi (transducer/strain gauge). The action was rebarreled even with what appeared to be .001 - .002 lug set back and is still going strong. Oh well, no sense trying present facts, such as actual pressure measurements of the concerned cartridges........which, btw, are completely in line with the original cartridge specifications used in the SR Mauser actions.

And as with the sleeved chambered .308W conversions in M95 Chilean SR Mauser, which is the real topic of this thread, they haven't grasped the fact it is the sleeved chamber that is the safety problem not the strength of the M95 action.

Larry Gibson

[JHeath]

Using lug setback to establish a "failure" threshold for an action is a good approach. Better than using the Kb threshold then applying a design factor.

I often deal with people in my industry who confuse their assumptions with fixed rules. Kind of like somebody in 1935 assuming that an N frame is only safe for historic .44 Special pressures because that's what is stamped on the barrel. Or conversely, like assuming that a Roller 7x57 can handle what a No. 1 can because that's what is stamped on the barrel.

The various historic cartridge pressures of a round for which a rifle was chambered, are not a "specification" of the action. They suggest what is safe, but don't say much about what is unsafe.

There's also the risk difference between likelihood and consequences. Safer to create a 50% chance of "Super face" in a 1911 by bulging a case, than to create a 20% chance of launching a 95 bolt through your head.

I am not drawn to marginal rifles with poor failure modes. Larry when guys with your experience are criticized for stepping over the caution tape with 95s or low numbered Springfields, I am on your side. Sometimes because the caution tape is 20' back from the edge. Other times because the caution tape is only 3' back from the edge but you can handle the risk.

[Larry Gibson]

JHeath

I no longer step over the caution tape with any action as I measure the pressures now. These days I do shoot loads in them having a measured comparable psi to the cartridges (actual measured psi's of original cartridges, not some quoted "specification") for which those actions were made. With my M91 Argentines (German made), my M95 (German made) and my M96 Swedish actions (Swedish and German made) there has never been any inkling of a problem. However, I have to admit those old .308W reloads, mostly with Hornady 165 SPBTs, at a measured 64,000+ psi were a few steps over the caution tape......:oops:

Looking at my old notes and knowing what I know now the velocities I was recording should have told me the loads were a bit too warm. However, "back in the day" I was going by the manual listed max loads and using CHE (Case Head Expansion) in load development. These days the manuals have toned down the "max" end of the old loads and we now know CHE is very unreliable......live and learn. None the less the M1916 Oveido survived and is still a good shootable action.

While I own 3 M1903s none of them are LSN'd '03s. I have never owned a LSN'd 03 myself. I have shot a few of them with issue M2 ball and cast bullet loads. I wouldn't hesitate to shoot one in good condition with a standard cast bullet load of say a 311291 over 28 gr 4895 with a Dacron filler. The measured psi is less than about half that of a 1906 cartridge. On the other hand my M1903A1 National Match Type II ( built on a SA DHT action) and my shooter M1903A1 (original SA DHT action and barrel) are shot with full service level M72 and M2 Ball level loads. I don't shoot my SC M1903A3 anymore since I found out it is as it came off the assembly line having only been inspected at Ogden Arsenal.

Excellent analogy using "the caution tape" btw.

Larry Gibson

[Multigunner]

What cartridge was the 1893 Spanish Mauser chambered for before the 7X57 Mauser cartridge was developed? What was the chamber pressure envelope of the Mauser Cartridges developed and marketed for use in the 1893 Mauser?

The Mauser 93-95 actions were designed to handle the pressures of cartridges that themselves were designed to deliver a specified performance, with a certain built in safety factor.

As I pointed out the action would when nearly new and in good condition handle at least one 58,000 CUP load without damage, it was never expected to handle magazine after magazine of cartridges at 58K CUP, if it had been the proof test loads would have generated far more than 58K CUP.
Some .308 Long Range target handloads found in the Hogdon loading data manuals generate aprox the same pressure ( in CUP) as the proof load used when the 93 was new.

The condition of far too many of the surviving 93 rifles suggests that even 7mm loads considered safe for the 98 actioned rifles in that chambering were a bit too hot for the 93. The Spanish manufactured 93 actions never had the reputation of being as strong as the original German made rifles, and more than likely any 7.62 chambered rifle with a 93 action that you'll run across will be a several times rebarreled Spanish knock off.

If Mauser had wanted a cartridge with the same velocity as the M118 they would have had no problem having the cartridge developed by DWM, but they would have had a much harder time producing a rifle to handle that sort of souped up 7mm in 1893.
The 7.65 Argentine Cartridge has much in common with the .308, but it was not loaded to the same pressure levels when the 1891 was the only vehicle for it.

Metal Fatigue is not only Cumulative its also "Accumulative", at a certain point crack propagation accelerates hastening failure.

I've said that I wouldn't want to subject a converted 93 action to a steady diet of pressures greater than 48,000 CUP , I suspect most people who have owned 93-95 actioned rifles would agree with me on that.
So what's so hard to understand about that?
There's certainly nothing to be gained by using hotter cartridges than the rifle was expected to digest.
Near as I can tell everyone on this board handloads. Its not as if the only cartridges available in 7.62 or .308 were those that generate the highest allowable pressures for those chamberings.
There's also no lack of stronger actions out there if one wishes to build a 7mm that they can soup up.

The Japanese sold Arisaka rifles chambered in 7X57 to the Mexicans, no doubt the Arisaka can handle just about any thing you want to stuff in it. The Mexicans bought up and built their own 98 actioned rifles as well, If the 93 was going to do the same job as well why go to the expense to replace it whenever possible?
By the 1950's the only countries still using the 93 were those who couldn't afford enough 98 rifles to arm all their troops, or constabulary where that applied. That includes Spain.
The rifle despite its many good qualities was obsolete. The Chileano was no great step forwards. Probably slightly better made with perhaps slightly better metallurgy, but not by much if any thing. Only real improvement was the small shoulder behind the bolt handle to form a very inadequate safety lug. Enough Boer Mauser bolts ended up in the shooters prefrontal lobes to suggest that little fix. Shoddy or degraded ammo in wartime was a fact of life.

[Larry Gibson]

Some still have a problem differentiating between CUP pressures and transducer measured pressures. Same still can't differentiate the difference between actual cartridge psi's and the maximum MAP specification for the cartridge. Boer Mauser bolts through their foreheads??????? The anti binding bolt guide on the M95 is oft referred to as a 3rd "safety lug" erroneously. Sheesh.......it never ends.......

Larry Gibson

[Tackleberry41]

We get different pressure and load data from companies in the US using the same equipment, much less a whole different method of measuring it in Europe. Apparently the Russians never even bothered with it as someone had to reverse engineer tokarev ammo to come up with some sort of pressure standard. Some of these limits do seem arbitrary. A report was posted on this site not long ago about flash hole size, which pretty much says, bigger works better. But nobody can seem to say where the original spec on flash hole size even came from. Doubt they put any testing into it to figure it out, and just said this size and its been that way since. Im willing to bet Mauser came up with the rifle, then they developed a load for it. It was right at the edge of the switch to smokeless and smaller calibers. And seems they would want a set velocity, with a max pressure, so long as a bullet went that fast, they cared little what the pressure was as long as it was below the max.

[Multigunner]

Some people can't recognize when someone else is trying to only compare the known records of Copper Units of Pressure of particular cartridges, and that Piezo electric measured PSI is not even secondary to those comparisons .
Interjecting in necessary lectures on the differences in CUP and PSI are nothing but a distraction from the major part of the subject in question.
There's zero information on Transducer readings of freshly manufactured 7mm Ball of the 19th century or the same ammunition after several years storage in a stable in Cuba because they did not have Piezo Electric transducers for many decades to come. Attempts to guesstimate the pressures by trying to duplicate the loads aren't likely to be productive since the propellants in use at the time haven't been available for generations. Testing any relic ammunition from those days is also unlikely to give even a ball park figure due to the effects of age no matter how well stored.

Luckily the U S Military procurement data sheets give the chamber pressures of most all 7.62X51 in use in Copper Units of Pressure as well as in the EPVAT transducer PSI measurements.
Metric Atmospheres and Kilograms per Square Centimeter may be confusing at times, but that is how Germany stated chamber pressures and Proof Test pressures in those days not in MegaPascals (MPa) as Europeans do these days.

[Larry Gibson]

"BTW; here is the U.S. Army's specification sheet for the M80 cartridge right out of TM 43-0001-27"

Notice the cartridge drawing on that page is of a .30-06 cartridge.
I mentioned earlier that those manuals are full of such errors, which is why you should go to the source material , the propellant procurement data........

You need to go back and look at the TM specification sheet again; The cartridge drawing gives the dimensions of the M80 Ball cartridge....2.8". That is a little shorter than the oal of the 30-06. No wonder we're having this discussion. The data sheets and manuals aren't in error.....your interpretation of them is.

Tomorrow I am going to test that 7x57 Chilean ammunition in the M95. I'm also going to test new Federal 175 gr SP factory 7x57 ammunition (no "degradation" of the powder from combat unless you consider gun stores as combat zones). Also will be testing some old Rem-UMC 175 factory ammo that never made it to a combat zone either.

To be fair also in .308W/7.62 NATO I have duplicated the M118 LR load using new IMR 4064 in LC Match cases with a Federal primer and 175 Sierra MKs. I will also be testing a couple lots of M80 and some M118 SB.

Time permitting I'll also test some South African .303 Mk 7, Remington 180 SP and 2 different lots of Winchester 180 SPs......the old Yellow box which has ball powder and new grey box which has extruded powder.

My measurements will not be in CUPs but in psi's. They will be comparative to each other if you understand nothing else. I will report the results tomorrow evening or on Wednesday.


Larry Gibson

[Larry Gibson]

Here’s the pressure data I’ve taken so far with the Chilean M95 7x57 Mauser using an Oehler M43 PBL. The M95 is in excellent condition, has been “sporterized”with the original milsurp barrel now 22” long. All measurements are in “psi’s”as to conform to SAAMI and C.I.P. psiMAP and PTc max measured with conformal peizo transducers. All the psi’s listed are not “absolute” as they were measured using the commercial and military grade ammunition made for such arms. As with measuring velocities, measuring the pressure on one day may not be the same as what is measured on another day can vary when tested even the very next day underthe same conditions. All testing was done using SAAMI testing procedures including the use of “reference” ammunition to obtain a “standard” psi measurement comparable to the standards set by SAAMIand C.I.P. All pressures shown are with the correction factor obtained through reference ammunition used. All velocities are muzzle velocities not screen velocities and are shown in fps. The psi figures are shown in thousands and hundreds, I. E.; 54,9 would be 54,900 psi.

All the following loads were tested yesterday. Ambient temperature ran from 70 to 80 degrees but all equipment including ammunition was shaded. Test consisted of 10 shots with the rifles switched after each test to keep the barrels cool. Two “foulers” were fired prior to each test string (as per SAAMI procedure). Yes it was a long 8+ hour day.

For the 7x57:
The SAAMI MAP is 51,0
The C.I.P. PTc maxis 57,0
Both are with transducer measurement.

Commercial Factory and hand loads:
Federal 175 RNSP; 49,9 2400
Rem-UMC 175 RNFMJ; 57,2 2311
Remington 175 RNSP; 48,2 2393
Winchester 175RNSP; 50,2 2376
My standard load 175 RNSP; 49,2 2334
Hornady Light Magnum 139 SPBT; 44,5 2624
My standard “light” hunting load 154 SP; 55,7 2579

Military Surplus:
CAVIM (Venezuela) 139 FMJBT; 46,0 2590
PS 1950 (Spanish) 154 FMJBT; 59,8 2442
PS 1951 (Spanish) 154 FMJBT; 60,5 2543
FAMME (Chile) 133 FMJBT; 55,3 2718
DWM 1918 (German) 172 Cupro RNFMJ; 54,8 2295

As we see the psi of both commercial and military ammunition made in 7x57 runs from 44,5 psi to 60.5 psi. Note the Chilean made military ammunition made for their own M95 Mauser gave a MAP of 55,3 psi, just under the C.I.P. PTc max of 57,0 psi.

Now, the original question of this thread was basically if 7.62 NATO ammunition would be safe in the M95s Chilean Mausers converted to “7.62. My response was if the M95s had new barrels most 7.62 NATO would be safe as most or the psi's of the ammunition over lapped. However, if the M9 5had a sleeved chamber and a rebored barrel then I would not feel it was safe. So now having some actual measured pressures of varied 7x57 ammunition let’s take a look at some actual pressures of varied .308W and 7.62 NATO ammunition actually measured with the same equipment.

The .308W/7.62 NATO test rifle was a M1909 Argentine M98 Mauser with a 24”heavy sporter contour barrel. The chamber was cut with a match reamer and headspace set to the minimum SAAMI specfor the .308W cartridge. Testing was done with the same Oehler M43 PBL using the same SAAMI testing technique as used testing the 7x57 ammunition. Reference ammunition was used to obtain the correction factor to give the psi as listed in thousands and hundred. The velocity is corrected to the muzzle and given in fps.


.308W/7.62 NATO:

SAAMI and C.I.P. MAP and PTc max; 62,000 psi as measured with transducers.

Commercial ammunition:
Winchester 150 PP; 61,7 2903
Remington 150 CL; 54,5 2924
Federal 150 PS; 57,3 2891
Winchester 180 PP; 57,7 2574

Military Ammunition:
M80 Ball WRA 68; 5 2,8 2790
M80 Ball LC 87; 61,2 2924
M80 Ball LC 90; 57,3 2852
CETME (Spanish) P 7.6 62; 58,7 2694
M118 SB LC 88; 62,9 2694
M118 LR (175 MK over 42.2 IMR 4064) LC 07; 59,9 2633
M852 MATCH LC 89; 59,0 2627
M852 duplication load (168 MK over 41.5 H4895, WLR, LCMatch case); 57,4 2670
M852 duplication load #2 (168 MK over 42.5 IMR4895, WLR,LC Match case): 61,3 2730

Thus we see here the psi of commercial .308W and military (U.S.) 7.62 NATO runs from 52,8 psi to 62,9 psi. Comparing the commercial ammunition psi’s to the M80 Ball psi’s we see there’s really not a lot of difference between .308W and 7.62 NATO. We also see that with the exception of 2 loads (one each commercial and M80 Ball) the rest fall within the psi’s the tested 7x57 ammunition psi range.

Those are the actual measured pressures of cartridges used in 7x57 and .308W/7.62 NATO rifles. Obviously the measured psi’s are different, as they should be, than the pressures listed on “data sheets”. All the measured pressures were within the SAAMI MPLM (Maximum Probable Lot Mean), EVPAT 7.62 criteria and the C.I.P. PK (Maximum Individual Statistical Pressure).

Larry Gibson

[CHeatermk3]

Thank you Larry for your excellent and illuminating work re the relative pressures of the ammo you tested.

Still glad I passed on the Chileno; found another one at a really good price in 7x57 to go alongside the one I already have.

[Multigunner]

I've mentioned before that the DWM ammunition produced from 1912 onward was intended for rifles like the Chilean 1912 Steyr a large ring Mauser action. I've also mentioned that during the Gran Chaco War older Small Ring Mauser rifles often failed when the newer hotter ammunition was used.
Besides the 98 actioned Mausers the combatants of that war routinely used Maxim and Madsen MGs chambered for the 7X57.
If IRRC Brazil bought a number of Maxim MGs in 7mm from Chile.

None of the military 7mm ammunition on the list was manufactured specifically for any Small Ring Mauser, during the Spanish Civil War even Spain was fielding WW1 surplus Gew98 rifles with barrels sleeved to 7mm and 7mm rifles with 98 actions bought from Serbia and other counties. I've not seen any problems of 98 actioned 7mm rifles being noted for severe lug setback.
George Orwell who fought for the Republican rebels wrote of complaints of the Spanish built 93 rifles failing in combat , sometimes with injuries to the shooters.
Use of the hotter post 1912 7mm cartridges explains why so many 1893-95 rifles exhibit lug setback.
Thanks for clearing that up, I'd hate to think those Small Ring Mauser actions were trashed by using only the proper standard 7mm Ball developed for these rifles when they were new.

[Larry Gibson]

Not worth wasting any more time........

[Larry Gibson]

Thank you Larry for your excellent and illuminating work re the relative pressures of the ammo you tested.

Still glad I passed on the Chileno; found another one at a really good price in 7x57 to go alongside the one I already have.

If you run across any Hornady 175 RNSPs you might try them under 47 - 48 gr H4831. I've had excellent accuracy in several different milsurp 7x57s with that load. The flat base and long bearing surface works well in the "oversize" Mauser bores. That hunting load with the Hornady 154 gr bullets also shoots to the sights on those regulated for the 154 gr FMJBT round, at least out to around 600 yards. If you've a rifle with sights regulated to the 133 gr Chilean FMJBT load (FAMME) then the Speer or Hornady 139 SPBT or the Sierra 140 SPBT over 52 gr H4831SC will duplicate the milsurp load and is very accurate in my M95 run at a sedate 49,000 psi.

Good going on finding another in 7x57.......much better that way.

Larry Gibson

And, they ain't bad with cast either......:drinks:

[CHeatermk3]

I have about 250 ea. Privi 174gn FMJBT bullets I bought to try to scrub the barrel of Chileno #1; what do you think of those loaded over 41-42.5 gns of AA2700? BTW I have a virgin keg of IMR4895 on hand too...

[Tackleberry41]

Larry you and your facts and data, when has that gotten anybody anywhere?

[Texas by God]

4 pages later I still respect both of you for your vast knowledge. Let's just enjoy our old SR Mausers with sensible loads.
Best, Thomas.

[Larry Gibson]

I have about 250 ea. Privi 174gn FMJBT bullets I bought to try to scrub the barrel of Chileno #1; what do you think of those loaded over 41-42.5 gns of AA2700? BTW I have a virgin keg of IMR4895 on hand too...

I've not worked with AA2700 but given it's burning rate it should do well with those 174s. Looking at Lyman's 49th Edition Reloading Manual you should be able to push them to 2200 - 2300 fps and maintain reasonable pressures in that load range. That IMR4895 should be a good powder for 130 - 140 gr bullets, it is for me with 120 - 130 gr. Should be able to push 2700 +/-. I've been testing some cast bullets with 4895, of course at much less velocity and pressure. The original powders used in the 7x57 with the 172 RMFMJs had burning rates similar in the 3031 - 4895 range. That Rem-UMC I tested had Hercules Lightening #1 powder in it......that goes back a ways......

Larry Gibson

[Larry Gibson]

Larry you and your facts and data, when has that gotten anybody anywhere?

This may answer your question.......

http://castboolits.gunloads.com/showthread.php?325191-Larry-Gibson-is-back

[Scharfschuetze]

I hope that you were just joking Tackleberry as that comment really doesn't sound like you. If it was just a humorous post, then please excuse the following comment. If not, well...

I'm certainly wiser for it. If it's an overload of important and esoteric technical data that applies to our hobby, just ignore it. I'm pretty sure that reviewing all sides of an argument is good for us all. As with a lot of things in life that offend you, you'll be happier if you ignore it. If you can't add anything applicable or important other than some veiled negative comment, why post? It costs nothing to be courteous.

[Tackleberry41]

I was joking same as the other times, they really need some sort of sarcasm font. Larry threw out a whole pile of data, stuff hard to argue with, well for most people anyways.

I wish I had the capability of measuring pressure. All I can do is go off whats in books, that varies wildly by who prints it. I went with a mild win 748 150gr SP load using some military brass I had. Then worked up a good 200gr cast load, and the other day a subsonic load. I swore it would be a zero dollar rifle, no scopes, no triggers, just shoot it as is. I did modify a williams sight to fit in the existing rear sight, so now it has a peep, which is a 1000% improvement over the original. The sight was in my parts bin. And I stuck it in the lathe to thread the barrel, give it a nice crown. I might break down and buy a recoil pad to fit to it soon, that metal one aint a whole lot of fun with full power loads.

[Scharfschuetze]

I was joking same as the other times, they really need some sort of sarcasm font. Larry threw out a whole pile of data, stuff hard to argue with, well for most people anyways.

Well I certainly misinterpreted your humor! Sorry about that. You are right, it is hard to ascertain humor in a thread when you're not able to read body language. I often just put a smiley face after a joking remark. I thought that there was an emotcon of a hand pulling a chain somewhere in the menue, but I can't seem to find in right now.

Ah, here it is. You can find it on the right side of the page after clicking on the "Go Advance" button. :kidding: