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?
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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?
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.
Read this before you pull the trigger
http://dutchman.rebooty.com/1895Chile.html
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.
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!).
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!!!!
"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.
Attachment 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
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 ++
"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.
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.
Attachment 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
Let's not forget all the 1893 Turk 7.65s converted to 7.92x57. They seem to hold up.
Best, Thomas.
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
Well now we know why so many 93 and 95 Mausers are found to have serious lug setback.
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.
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
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=Yg...page&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.
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
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.
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
"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.
This may be the proper PDF file
https://www.google.com/url?q=http://...52C7FzXpa62yGQ
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
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
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
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.
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
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
"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.
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 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 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.
Double post, can't edit or delete
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.
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.
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
"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.
"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