308 win in 1895 Chileno??

[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/M...T3).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://...52C7FzXpa62yGQ

[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......

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

Attachment 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-S...T-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.

Attachment 190747

Larry Gibson