Hey Peter, There are a bunch of us out here that don't claim to know it all - like larry does . larry even "claims" accuracy tighter with his Haphazard(Dr. Oehler's word) SGS than the guy who designed it(Dr. Oehler) says is normal for the home user. And larry thinks everyone will believe him instead of Dr. Oehler.

Speaking of Dr. Oehler, he likes to use the term Reference Ammunition instead of Calibration Ammo when it comes to properly Setting-Up a SGS. And low and behold, Speer even discusses how to Calibrate Pressure Testing Equipment using Reference Ammunition or Calibration Ammo in Manual #13 too. Imagine that, I was RIGHT AGAIN!!!!

Anyone with even the most basic understanding of Measuring Devices knows that they must be properly Calibrated - prior to being used - that would mean Calibrated to a Known Standard. Dr. Oehler knows, Speer knows, but for some reason larry is clueless concerning this most basic fact and still believes he knows what he is doing.
-----

I do make some strange typing errors from time to time. So I do appreciate it when someone catches them. After you had pointed out that obvious error, I noticed I'd posted that larry had said something "Relevant" to the conversation. Nope, it should have been "Irrelevant", so I went back and got that changed too.

The thing with larry's posts is even when a person points out the totally WRONG and FALSE brain-dead assumptions he has made, he still can't figure it out. Same with alf, same-e-same with jagter. Pitiful!

I don't mind pointing out that Speer has gone from Copper Crusher to Piezoelectric Testing on some Cartridges, but they sure have not abandoned the time-proven CHE Pressure Detection Method - on ANY Cartridge. And for those who don't want to read how to use the very best and only accurate means of Pressure Detection Methods, good old CHE and the never-fail PRE, for us typical Reloaders, Speer has the wisdom to list how to do it in their Manuals.

I do not remember Speer "consulting" with larry before selecting any of their Test Methods.

Hot Core

I'm not going to again call you a liar however you sure do take things out of context. Here is what I actually said;

"The use of the M43 with strain gauge provides pressure readings quite consistent with the other methods used. General those are within +/- a few percent. On a pressure reading of 50,000 for instance a 3% difference is +/- 1,500. Since pressures are generally rounded off in manuals and factory charts in a minimum of 1,000 the results are well within accepted variations."

Now just where in that is; "larry even "claims" accuracy tighter with his Haphazard(Dr. Oehler's word) SGS than the guy who designed it(Dr. Oehler"

So everyone now see's quite plainly that you are wrong. I never "claimed" any accuracy standard. Now is that a lie or are you just confused. Actually Dr. Oehler does state that the M43 reading are quite consistant with industry used devices.

Still on that "calibration ammo" kick.....you still haven't contacted SAAMI to ask them for some have you? No I didn't think so, you simply misconstruing what you read to fit your own simple minded obsession with CHE/PRE.

I may be "brain dead" but it is an accident of birth. You however are an idiot by choice. (yes I did plaguerize a line out of a movie)

No Speer never did "consult" with me nor have they consulted with you. Get real.

Larry Gibson

caliated using referenca ammunition?

you mean like some ammo with a known pressure?
like some that has been fired in this gun
previously?
if you get the same readings it would be reading
the same then?
if somewhat off this would be your calibration.

i don't even have one of these but it seems
relatively simpleto obtain "reference ammo"

Lamar

A known pressure in what? A SAAMI test barrel? A CIP test barrel? or your everyday off the shelf rifle. But wait there's more...who's off the shelf rifle? Ever wonder why when you chronograph the same load out of two seemingly identical rifles you get different velocities? It's because the pressures are different in the two seemingly the same rifles.

That's why there is no such thing as "calibration ammunition". There is only reference ammunition. The pressure that Hornady gets with that ammo is different than what Sierra gets which is different than what Speer gets, etc. The reason it is different is because even with the minimum spec SAAMI test barrels they all are different. Also the test device themselves are some what different.

Hot Core cracks me up...hell, he is the resident expert here. I'm only calling him on his continued use of CHE as absolutely being reliable. It isn't. What he doesn't seem to know in his continued droning about reference ammunition is that the conformal transducer is calibrated with hydraulic oil pressure not "calibration ammunition". Those are used by SAAMI. the military on the other hand uses a gas piezoelectric transducer that is located in the barrel just in front of the case mouth. It is calibrated with hydraulic pressure and/or by mounting a reference transducer on the barrel. It also is not "calibrated" with "calibration ammunition". The use of a copper crusher to test peak pressure is also still recognized by SAAMI. The little crushed copper pellets are calibrated by hydraulic pressure as represented in a tarage table. "Calibration ammunition" is not used to "calibrate the copper pellets. Strain gauge calibrations are made from the measurements of the barrel dimensions where they are mounted and the assumed modulas of elasticity of barrel steel. That is a common engineering method. The strain gauges themselves are calibrated and that is entered into the computed information.

Thus we see that nowhere is “calibration ammunition used to calibrate the pressure measuring device.

There is such a thing as “reference ammunitionâ€. Reference ammunition is a single lot of factory ammunition known for its consistency. It is used as a reference with pressure measuring devices It is not used for “calibrationâ€. If one is using a strain gauge then testing several different types of factory ammunition gives you a “referenceâ€. It’s the same thing.

Larry Gibson

quote:

Originally posted by Lamar:
caliated using referenca ammunition? you mean like some ammo with a known pressure?

Hey Lamar, Yes to both.

quote:

like some that has been fired in this gun previously?

No, because you don't know what the Pressure of it would be to start with.

quote:

if you get the same readings it would be reading the same then? if somewhat off this would be your calibration.

I'm not sure what you are asking.

If you are asking if you shoot multiple cartridges from the same box and they give the same Pressure Indication(orrelatively close because they WILL NOT all be the same) is the System Calibrated - then the answer is still NO! And for the same reason, you DO NOT know what the actual Pressure of that ammunition is to start with.

quote:

i don't even have one of these but it seems relatively simple to obtain "reference ammo"

All it takes is money and purchasing SAAMI Reference Ammunition(Calibration Ammo).
-----

I already mentioned how the Industry Calibrates their Pressure Equipment with Reference Ammunition and I mentioned it could be found on page 53 of Speer Manual #13. Just looked in Speer #12 and it is on page 55 along with how they use CHE. Using Reference Ammunition(Calibration Ammo) allows the user to determine how much "Pressure Correction Factor" needs to be calculated in, to compensate for the differences between the Test Equipment being Calibrated, in comparison to the Known Standard. All of which can be read about in the Speer Manuals.
-----

Looking at larry's last posts makes me wonder what his real motive is. I know of no one in the industry who Calibrates their Pressure Testing Equipment with "oil". The reason for it is quite simple, the "oil" is not an Approved Standard for Calibrating Pressure Barrels used to Test Cartridges. Plus, it would not work due to the "oil" being able to slip past the Case. They are only Sealed Systems when an actual Cartride is used, but I can see how larry would be clueless about that.

However, "oil" is used for some Pressure Testing, but it just won't do in a Cartridge Pressure Gun. This gets back to where I mentioned larry uses some Accurate Facts that are Irrelevant to the discussion. His inability to differentiate between these issues is amusing to me, but can be very misleading to people trying to understand Ballistics.

larry's totally incorrect and not even close to reality posts are quite similar to the improper conclusions that alf makes when he reads things and attempts to make comparisons with ballistics. They apparently read something and try to apply it to firearms and ballistics where there is zero correlation and thus draw very improper and totally wrong conclusions. However, their posts are ALWAYS good for plenty of

For example, in larry's previous post he called me a Lier. Then in his next post he claimed he had not called me a Lier. and in a post just above, he says, "I'm not going to again call you a liar...". That is the problem when larry refuses to speak the truth, he isn't nearly smart enough to keep up with all the incorrect and totally false things he blathers on about. Thus he gets caught in his own words. Pathetic and pitiful.

Hot Core has consistently avoided the truth, perhaps that does make him a liar. I’ll leave that up to all of you to decide.

I and others have repeatedly asked him to check with SAAMI regards his claims and specifically regards to “calibration†ammunition. He fails to do so or perhaps he has and knows the truth but does not want to admit he is wrong. However any of you can easily check with SAAMI. Their website is;
http://www.saami.org/Glossary/display.cfm?letter=A .

At that site you will find all the definitions of the terms that SAAMI uses. You will not find “calibration ammunition†and you will not find CHE or PRE. What you will find is the definition of “reference ammunitionâ€. That definition is;

AMMUNITION, REFERENCE
Ammunition use in test ranges to evaluate test barrels, ranges and other velocity and pressure measuring equipment. May also be used as a control sample by which other characteristics are compared, such as accuracy, patterns, etc.

Note that reference ammunition is used to “evaluate†and to use as a “controlâ€. Reference ammunition is not used to “calibrateâ€. Thus is the same with a strain gauge, factory ammunition is used to evaluate and as a control.

The following is a quote from an article recently written by Richard Patterson, Managing Director, Sporting Arms and Ammunition Manufacturers’ Institute;

“SAAMI has standards for the dimensions and operating procedures for the test barrels that ammunition manufacturers use to test the operating pressures of each lot of ammunition. SAAMI establishes pressure reference ammunition that is used throughout the industry to ensure consistency with pressure testing equipment.â€

So there you have it from the managing director of SAAMI. Reference ammunition is used to “ensure consistency†with pressure equipment. It is not to “calibrate†that pressure testing equipment.

Now Hot Core will try to argue “semantics†here but please read the following on reference ammunition. Please pay particular attention to the part I have put in bold. Then refer back to Hot Core’s accusations of me; “the problem when larry refuses to speak the truth, he isn't nearly smart enough to keep up with all the incorrect and totally false things he blathers on about. Thus he gets caught in his own words. Pathetic and pitiful.†I’ll then put it to you as to who is a liar, who is “isn’t nearly smart enough†and who is really posting things that “totally falseâ€.

[I]“Reference Ammunition [/I]

Under SAAMI specifications, reference ammunition is required only for the qualification of new pressure barrels. A new pressure barrel must demonstrate it generates nearly the same pressure and velocity as existing SAAMI spec. pressure barrels. Reference ammunition is as uniform as possible, and ideally all pressure barrels will show the same indicated pressure and velocity. If one barrel is found to be different, something is off in either the barrel or its sensors.

Continued in next post

Continued from previous post.

Reference ammunition is not used to calibrate pressure sensors. Piezo systems are calibrated hydraulically. Crushers are calibrated by the manufacturer. (The use of reference ammunition to try to correct crusher measurements is listed as "optional.") To quote SAAMI: "Reference Ammunition cannot guarantee the absolute accuracy of any test system."

CIP procedures permit the use of reference ammunition to correct pressure readings taken at any one lab. The reference ammo has been fired at several trusted labs, and the average of these readings is the reference value. Reference cartridge pressures measured at any other lab are compared to the reference value, and if the difference is less than 10%, the offset can be used as the correction in subsequent tests at that lab.
Statistics
(Sorry, this section is necessarily heavy in jargon.)
More than with many physical measurements, that of chamber pressure displays a large scatter. For this reason, SAAMI defines pressure ratings in statistical terms.
In the table above, SAAMI's Maximum Average Pressure (MAP) is listed. This is the number often quoted as the SAAMI "pressure rating," and SAAMI states the MAP "is the recommended maximum pressure level for loading commercial sporting ammunition." When loads are worked up either for production or for presentation in load books, they will be limited to the MAP, and for most practical purposes, this is the cartridge's rating.
The MAP can be a bit lower than the average in a large lot of ammunition. To determine pressure, SAAMI recommends 10 rounds be tested and averaged. With such a sampling size, there is a chance this average pressure could be below that of the larger lot. Basic statistical considerations would place the average for large lots to likely be within 2 "standard errors" of this smaller sampling. For ammunition testing, SAAMI suggests 2 standard errors will be about 2.5% of the MAP, and adding this to the MAP gives SAAMI's Maximum Probable Lot Mean (MPLM).
This MPLM is the pressure for which a gun should be designed since it is possible large runs of ammunition could average this pressure. The MPLM is, then, the actual pressure rating of the cartridge, and the SAAMI proof loads are defined relative to MPLM, specifically between 30 and 40 percent over MPLM. (Since MPLM is 2.5% over the 10 shot MAP, the compounded result is proof loads are between 33 and 44 percent of the MAP shown in the table.)
An average over 10 rounds could be below the MPLM (as reflected in the lower MAP rating), or it could be above the MPLM. When testing a lot of production ammunition, SAAMI recommends no 10 round average exceed the Maximum Probable Sample Mean (MPSM). Based again on statistics, the MPSM is taken to be 6.3% over the MAP. (While a load developed to MAP could be over the average for the production lot, the proof load is developed on the assumption the MAP was below the MPLM, therefore it's safe to assume the MPSM is above MPLM as well.)
Lastly, there is the Maximum Extreme Variation (MEV). There is a small chance that in a very large lot of ammunition, a single sample might test much higher than the averages. From statistics, SAAMI recommends an MEV no more than 20.6% above the MAP. Keep in mind that though a single cartridge might approach MEV, averages over 10 cartridges must continue to fall near MPLM (and below MPSM), so it is unlikely any significant number of cartridges approaching MEV will pass through.
To summarize, SAAMI pressure ratings reflect load development done with pressures limited to the MAP. In large production lots, the average could be a bit higher but likely will be below the MPLM. The worst case sampling of 10 in the production lot shouldn't exceed the MPSM, and the worst case single cartridge shouldn't exceed the MEV.
The CIP ratings are equivalent to SAAMI's MPLM, and this difference in definitions for the pressure rating likely explains why the CIP numbers are generally a bit higher than SAAMI's. The CIP equivalent to SAAMI's MEV is 15% over the rating (relative to MPLM, SAAMI's MEV is 17.7% over). “
That was pretty long but in there you can see that the pressure figures given are not definitive. To arrive at the MAP averages and percentages are used as well as accepted percentages over or under the MAP. That is industry standard, that is scientific standard and that is as I presented it. Notice in the bold high lighted part where it says “calibrated hydraulicallyâ€. Notice where it says "Reference Ammunition cannot guarantee the absolute accuracy of any test system."
CIP procedures permit the use of reference ammunition to correct pressure readings taken at any one lab. The reference ammo has been fired at several trusted labs, and the average of these readings is the reference value. Reference cartridge pressures measured at any other lab are compared to the reference value, and if the difference is less than 10%, the offset can be used as the correction in subsequent tests at that lab.

I deal with facts and so should you. You or anyone, including Hot Core, can Google “SAAMI pressure equipment or calibration equipment†or other such words and find a wealth of information. Apparently Hot Core isn’t smart enough to do that before he shoots off his mouth. Or he has Google’d for the information or has actually contacted SAAMI about it but yet continues to lie. He doesn’t realize it is too easy to get caught in BS and lies these days.

Hot Core has been caught in his BS and lies.

Larry Gibson

All of the above post is a quote from SAAMI literature with the exception of the last paragraph.

Larry Gibson

And for more correct informtion, you can look at pages 108 in Speer #10 and page 16 in Hornady #3.

Does look as if larry is busy copying Irrelevant info and continuing to call me a Lier. Speaks well for his character.

Hot Core

It is rather obvious who the "charactor" is here. You can't stand the facts. That was a rather short come back for you, lost for words about the facts of what SAAMI has to say..... Go back and read your own BS and lies. Then read the above as it is what SAAMI says. They are the industry leader that sets the "standards". What about the "oils" and the "calibration" ammo? No comment? You and your BS and lies have been proved wrong. You know it and everyone else does too.

Now you're trying to quote something from Speer. Why don't you post it here for everyone to read and compare it to what SAAMI says. You might want to remember we all have Speer manuals too so be careful not to quote out of context. Keep to the facts for once and cut the BS and lies.

Larry Gibson

the problem i have with case head expansion
measuring is that factory ammo is made
to fit the smallest chambers.
mine aren't the smallest,one in particular is bigger then the standard wild-cat.
man if i measured che even a 1200fps cast bullet
would be over pressure by 3 times as much as
the maximum.

/

quote:

who Calibrates their Pressure Testing Equipment with "oil".

I don't want to get into the middle of this but a standard method for statically calibrating pressure instrumentation (like gauges) is to use a dead weight tester, which uses hydraulic "oil."

Hey Will, Glad you jumped in. How about doing us a favor and call a couple of the Bullet and Powder manufacturers and asking them a single question? If not Will, maybe Peter?

I'll even provide the phone numbers:
(913) 362-9455 Hodgdon Powder

I had Toll Free numbers here somewhere for all of them, and can't find that Address Book. But, I'll be glad to look for it.

Just found it:
(800) 338-3220 Hornady Bullets
(800) 497-1007 Ramshot/Accurate Powder
(800) 356-2666 Winchester Powder
(800) 276-9337 Alliant Powder
(800) 574-9200 Barnes Bullets
(800) 223-8799 Sierra Bullets
(800) 285-3701 Nosler Bullets
(800) 276-9337 Speer Bullets

Here is what needs to be asked after you get ahold of their Quality Manager:

1. Do you Calibrate your Pressure Test Guns with SAAMI Reference Ammunition(Calibration Ammo), or do you use oil?

Then post what they said. The only problem will be larry calling everyone, including those in the manufacturing facilities, Liers.

/

Can we get back to the original question? While (some) of the ensuing discussions has been interesting there are aspects of the original question that have gone unanswered.
1. Why don't the reloading manuals provide data for components used to reload 7x57 ammo in modern rifles? They do so for 45 Colt, 45/70 etc.
2. In the absence of such reloading data, how should one proceed? One answer is: "don't". The original data for the 7x57 worked fine for 100 years or so. Another answer is "look for visual signs of high pressure". It is the third answer "well modern rifles fire 270 loads of pressure X therefore your 7x57 can safely function up to those pressures" that has got us into the above discussion.
3. How much value is pressure test data if it is not measured in your rifle?
Peter.

quote:

1. Why don't the reloading manuals provide data for components used to reload 7x57 ammo in modern rifles? They do so for 45 Colt, 45/70 etc.

They do.....Hornady's manual says this about the data for 7 X 57:
we developed this data in the strong modern Winchester Model 70. This data should not be used in the older Mauser Model 93 or 95 and should be worked up to carefully in M-98 Mausers.

Hodgdon's manual shows CUP data with their data so you have some reference for your own personal loads

quote:

2. In the absence of such reloading data, how should one proceed? One answer is: "don't". The original data for the 7x57 worked fine for 100 years or so. Another answer is "look for visual signs of high pressure". It is the third answer "well modern rifles fire 270 loads of pressure X therefore your 7x57 can safely function up to those pressures" that has got us into the above discussion.

Everyone to their own....but see the replies to the other two questions.

quote:

3. How much value is pressure test data if it is not measured in your rifle?
Peter.

IMO it has lots of value as a reference for the potential of reloading. If I see a load is measured at 45,000 CUP then it tells me I might be able to move it up a bit if I'm careful. However if the loading data shows 53,000 CUP I know that this just might be all she wrote for a reloader. It means there is or is not much potential for a reloader.

Alf

Excellent post. Unfortuneately Hot Core cannot understand the differences you are talking about.

Larry Gibson

Vapodog

I am home and have access to the 7x57 pressure information from measuring a few loads in my own 7x57. You had ask for them. Keep in mind my rifle is a sporterized M95 Chilean Mauser made by Loewe. It is in excellent condition and the barrel is 22". The SAAMI MAP CUP for the 7x57 is 46,000 and the PSI is 51,000. In working up the loads I tested with the M43 I did exceed the 51,000 PSI figure but not by much.

Do you still want the information posted?

Larry Gibson

quote:

Do you still want the information posted?

Thank you but the only 7 X 57 load data I would like is something that the prsenter believes is roughly 62-65,000 PSI....to me it's not important how one measures his data.....I will work up to it anyway on my own....the internet being what it is!!!

Vapodog

That's ok, I didn't want to punch it up that high in my M95. I'll just give you a few of the top loads for S&Gs. That might give you some place to work from.

All cases were WW 7mm Mauser once fired.
Cases were neck sized.
Primers were WLRs.
Since the throat is long on this rifle all loads were seated to magazine AOL of 3.05"
All pressures are listed as average peak pressure in psi (M43)


Factory Hornady Light Magnum 139 gr SPBT/2624 fps/44,200 psi

Hornady 139 BTSP/53.5 H4831SC/2690 fps/53,100 psi

Hornady 139 SPBT/50 IMR 4350/2746 fps/55,400 psi

Hornady 139 SPBT/46 Varget/2748 fps/56,300 psi

Rem 150 CoreLok/51 RL19/2517 fps/44,800 psi

Hornady 154 SP/53 H4831SC/2618 fps/57,800 psi

Hornady 175 RN/51 gr Old 4831/2481 fps/56,200 psi

Again those are the maximum loads I worked up to. The loads I actually use are in the 51,000 psi with this M95.

These were once fired cases as mentioned. That is what Hot Core, Speer and Hornady, in their old manuals, say to use for CHE measurements. Since I conducted this test with the on going debate raging on CHE I also measured the cases for CHE. Out of 100 cases in this test with measured pressures ranging from 38,000 to 58,000 psi I found only one case that gave any CHE measurement. One case showed an increase in of .00015" CHE at 57,900 psi. The other 4 cases with that same load showed similar pressure (average was 57,800 psi) but none showed any measureable CHE. That one case did not have the high pressure for that load.

Using CHE as the "pressure indicator" I would have been way over the pressure I want to use in this rifle.

Larry Gibson

quote:

How much value is pressure test data if it is not measured in your rifle?

This is an interesting question as it really speaks to the question as to how much difference there is from rifle to rifle when shot with say ammo from a Reference load batch.

This where the the whole "CIP package" becomes interesting because the CIP proof not only looks at pressure values but also dictates chamber and barrel dimension minimums and maximums.

This means in reality that if one were to take a number of say Sauer rifles which have barrels within the CIP spec range and fire a batch of CIP spec ammo say RWS factory rounds ( of the same batch) through them one would only get a 4 % variance in pressure between the different rifle barrels. In fact they guarentee a 4% variation limit if the barrel dimensions are within the dimension limits.

This is in effect what the proof sets out to achieve, repeatability to a statistical significant number between rifles with the same barrel spec ( within the mini and maxi dimensional limits) when shot with the same batch of proofed ammunition.

This means in reality that if one were to take a number of say Sauer rifles which have barrels within the CIP spec range and fire a batch of CIP spec ammo say RWS factory rounds ( of the same batch) through them one would only get a 4 % variance in pressure between the different rifle barrels. In fact they guarentee a 4% variation limit if the barrel dimensions are within the dimension limits.

However, ALF, if I understand your earlier comments, the absolute number reached ie. XXXX has no real objective meaning ie. if I were to use a Remington rifle, I could get a totally different number. And this is because there is no (objective) calibration.
Am I making sense here? That is, the reference load batch is really for uniformity ie. samples will show similar numbers within the specifications, not because they are proof loads, or because they are known to cause certain CIP numbers in a test barrel.
Do I have this right?
Peter.

Peter

Another point to remember is that SAAMI specifies test barrel dimensions. They are the minimum dimensions for chambers and bareels. The test barrels are then made to those very rigid specifications. However with factory rifles like the Rmington you mention the dimensions are seldom anywhere close to minimum. Thus the pressure of reference ammunition will always be higher in SAAMI test barrels than it is in your Remington.

The reality check here is that we all know that fire formed cases that are neck sized usuall will only fit back into the chamber they were fired in. That tells us there is really not much interchangeabilty in chambers. Barrel bore dimensions also vary to a good degree. This why we have "fast" barrels and "slow" barrels when we chronograph the same ammo in differrent rifles that appear identical. That's all that reference ammuntion does. It is not used to calibrate pressure measuring devices. It is only used as a "reference", hence it's name.

Larry Gibson

larry
the rl-19 51.3gr and hornady 139 spire-point plain base, gives 2750 from the wifes 7x57
but it likes the257+p brass.
my A.I. with rem brass likes 52.3 gr to get
2775. same bullet.
just giving you some numbers here.
and nothing that has been shot with either of these deer,elk,or range bulls
wander off.....don't ask about the bulls..

i really don't understand the need for the h.v
it really is much easier to match the bullet to the velocity it is going to be used at..

Lamar

I don't know the need for HV either other than if I had a 7x57 on a modern or M98 action I would probably load it up to 60,000psi, it's potential. However the little M95 I have was sporterized into a Mannlicher using the original military stock. I don't know who did it but they did a pretty decent job. I converted it to cock on open and put a Redfield reciever sight and a Williams Hooded post up front. Makes for a sweet little rifle and extremely accurate. I actually use the 139s over 44 gr of varget which duplicates the Hornady LM but with 51,000 psi. That is plenty of deer medicine. With the 175 Hornady RN or SP at 2400 fps, again at 51,000 psi, it makes for a dandy elk or bear cartridge (elephant too if you've read Bell). With the original steel butt plate that is about all I like out of the little rifle as she only weights 7.5 lbs. Sweet though.

Larry Gibson

Now I see what you all are talking about. Yes, larry is saying one thing and doing another just as you all mentioned in the email.

quote:

Originally posted by Larry Gibson:
...All pressures are listed as average peak pressure in psi (M43)

No need to repeat the "Numbers" since larry really doesn't have a clue about what the REAL Pressure happens to be.

quote:

I also measured the cases for CHE. ...Using CHE as the "pressure indicator" I would have been way over the pressure I want to use in this rifle.

Actually larry has gone and used what he is telling everyone not to use. Must be to make sure he doesn't blow-up the old rag rifle with "Numbers" from a Non-Calibrated, Guessed at Dimensions, Fudge Factored, Haphazard SGS.

Actually, he should have used both CHE and PRE. And in an old rag rifle, it is NEVER a good idea to exceed the Benchmark Standard PRE of the factory ammo. And yes, I can see why he doesn't want to try using PRE, it works and a Haphazard SGS that he has totally wasted lots of money on is simply Guessing and Hoping.

An emailer wanted me to mention that Harbor Freight recently had 0.0001" capable Micrometers for $19.99. And he wanted to also mention that larry probably wasted close to $4K on the Haphazard SGS, with the cost of a Laptop if he did not have one. That would be 200 times the cost of the most reliable, time proven, venerable - PRE Micrometers. Couldn't happen to a more "deserving fellow".
-----

And yes, as those of you who called determined, the factories do Calibrate their Pressure Guns with Reference(aka Calibration) ammo. Who was it that mentioned that?

Hot Core

I had a whole post but deleted it. You and your dumb ass remarks aren't worth the effort or time.

Larry Gibson

quote:

What they forget is that muzzle energy is linked directly to mean barrel presssure and ultimately chamber pressure. So if the velocity is high it comes at a price and the price is pressure!

Methinks this entire discussion has reached the "tempest in a teapot" stage!!

Yes, high velocities are paid for by pressure. BUT, higher performance levels can be reached either by HIGHER PRESSURES, or lower pressures SUSTAINED FOR A GREATER PORTION OF THE BULLET'S TRAVEL TO THE MUZZLE, WITHOUT EXCEEDING SAFE PEAK LEVELS.

So if you can find a high density-per-volume powder that allows you to get enough of it into a given cartridge case, it is possible to get higher-than-usual velocities from that cartridge/bullet combo than you could safely attain with acceptable pressures using faster or less dense powders. There are a couple of powders that demonstrate this type of performance when used with heavy bullets in the 7X57mm. BUT, these same propellants are much less effective when used with lighter bullets, because you can't get enough of them into the case to attain the same benefits as are produced using heavier projectiles.

quote:

With the 175 Hornady RN or SP at 2400 fps, again at 51,000 psi, it makes for a dandy elk or bear cartridge (elephant too if you've read Bell).

Larry,

This combination (175 gr @ 2,400 fps) is as much as we will ever need for medium sized game. In fact the 7x57 made its name with 173/175 grain conventional bullets around 2,300 fps. In later years, with modern powders, it climb to around 2,400 fps. Quite adequate for Kudu or Elk, as proven hundreds of times over.

PMP, our local producer of ammo, loads a 170 grainer to 2,428 fps. These modest velocities made for good terminal performance down range at lower impact velocities. Hence the surprise to other hunters with much faster calibers such as the 7 mm Rem Mag, as they think in the American adage that the "faster bullet hits harder at all ranges" instead of realising that it works negatively against bullet performance.

With the advent of premium-grade bullets it even gets better for us, with better weight retention ratio's and evenly formed mushrooms. Various tests indicate best bullet performance between 2,100 AND 2,200 fps impact velocities for most bullets. Another side benefit is lower levels of meat damage especially in comparison with old fashioned frangible conventional bullets that shatter at higher velocities.

Warrior

quote:

Originally posted by Warrior:
...the surprise to other hunters with much faster calibers such as the 7 mm Rem Mag as they think in the American adage that the "faster bullet hits harder at all ranges" instead of realising that it works negatively against bullet performance. ...

I've seen a few of Warrior's comments and they do appear to have a first-hand experience knowledge base similar to alf, larry and jagter - nearly non-existant.

Actually, Warrior's above statement is totally and completely WRONG. High Velocity is no detrement when the proper Bullet is selected. How people come up with such foolish thoughts, that more Velocity is a problem simply amazes me.

It is simply the selection of the proper Bullet for the intended Impact Velocity. There are various Bullet Designs which will provide what you want at what ever Impact Velocity you expect.:
1. If you want quick expansion and shorter penetration, the proper Bullet is available.
2. If you want slower expansion and a bit deeper penetration, the proper Bullet is available.
3. If you want very slow expansion and very deep penetration, the proper Bullet is available.
4. If you want no expansion and lots of penetration, the proper Bullet is available.

There is nothing at all wrong with High Velocity. There are however people who choose the wrong Bullet Design Envelope for the task at hand.

Hot Core,

You misread my post totally. It is mainly applicable to Softs that the majority of people are using, especially those that buy over the counter ammo. Each bullet type has it own "velocity window" in which it is most effective - broadly one could categorise them in:

1) Conventional bullets that are frangible (as my post referred to them in the main)

2) Partition non-bonded bullets (front end shatters and lose about 40% of its weight)

3) Bonded bullets - various kinds and they differ in weight retention and expansion.

4) Partitioned bullets that are bonded (Swift A-Frame and NP Gold)

5) Solid Shank bullets - Rhino, NF, Bear Claw & Kodiak)

6) Expanding monolithics - Barnes & GSC

7) Non- expanding solids of various types.

So, we do not actually differ, but the fact remains if you exceed a bullet's threshold strength the velocity becomes counter productive. My post just high-lights the critical importance of bullet performance, and in the case of the 7x57 mm with its modest velocity, conventional bullets perform better than within their faster rivals, as the impact velocities down range happens to fall in the "velocity window" of those frangible conventional bullets, that most people are still using today. (You can check sales statistics of ammo shops - reloaders make up a tiny percentage).

What amazes me was that you could misread a simple post like this, and then at the same time makes a personal attack, much in line with the condescending way of talk against Alf, Larry and Jagter (labeling them as brain-dead).

Please read Rick Jamison's article in Shooting Times of October 2002. It is not sensible to shoot soft expanding bullets at hyper velocities, as they behave in a similar fashion when you throw a tomato against a wall. Essentially Jamison demonstrated that at 2,000 fps impact velocity, all 17 bullets tested retained more than 85% of their weight, whereas at 3,000 fps it is a grim sight. Then in July 2004 Jamison writes in Petersen's Hunting magazine (page 63) about how bond-core bullets perform. All bullets expanded reliably at 2,000 fps and look as perfect as you want them to be. At 3,000 fps though, most of them look like a small blob of metal or totally over-expanded.

Warrior

Photo of 7 mm bullets shot into a wetpack of newspaper at 25 yds:



Left to right:
175 gr Barnes-X bullet - 100% weight retention
160 gr Nosler Partition - lost its front core
175 gr Claw bond-core bullet - bonded core peels with copper jacket to form more sturdy petals
175 gr Sierra Game King bullet - lost all its lead, only the jacket remained.

Clearly bullet performance differ drastically.

Warrior

quote:

Originally posted by Warrior:
Hot Core, You misread my post totally. ...

No, I don't think so. It is the same bunch of and ignorance you posted in the thread where the guy was going Elk Hunting and you started posting about 0.458" Bullets "Breaking Up". When questioned in that post, you refused to mention even "one" conventional 0.458" Bullet that would Break Up on an Elk. Everyone knew why, because it is pure

You, larry, alf and jagter simply do not understand a lot of the things you all really believe you have great knowledge about. I don't know why you all have been mislead into the illogical and WRONG thoughts you all have concerning Ballistics, but when you post foolishness on this Board, there are people who really do understand the topic and do not allow it to stand without being corrected. If it wasn't for you all totally misleading the Beginners and Rookies, I'd be happy to sit back at laugh at you all without ever making a post.

Most folks would rather not post at all than get into the arguments. If there is some way to keep the Beginners and Rookies from being totally mislead by those that are seriously WRONG, I'll be glad to go that route. If anyone has a suggestion how to accomplish that I'd be interested in hearing about it. Feel free to PM me with the answer, or let us all hear about it, either way, I'm interested.
-----

quote:

Originally posted by Will:
I don't want to get into the middle of this but a standard method for statically calibrating pressure instrumentation (like gauges) is to use a dead weight tester, which uses hydraulic "oil."

Hey Will, If you are still around and would like to discuss the Oil Calibration, I'm interested. It is used in "one" place within the Ballistics Industry that I'm aware of. And I know why.

Anyway, if you would like to discuss "How" it could be used on a Pressure Gun, and "Why" it isn't, I feel sure there are people who would like to learn about it. We can even start a separate thread if you would like that.

Or anyone else that actually knows about Oil Calibration.

quote:

It is the same bunch of and ignorance you posted in the thread where the guy was going Elk Hunting and you started posting about 0.458" Bullets "Breaking Up". When questioned in that post, you refused to mention even "one" conventional 0.458" Bullet that would Break Up on an Elk. Everyone knew why, because it is pure

The only bullshit is that you decide what is bullshit and what not. You are the one that is ignorant and full of bullshit in believing that conventional .458 bullets cannot breakup on game. Here are some pics for you. Claw bullets that failed on game - the first 3 bullets come out of game and the 4 th one is another Claw bullet that has been sectioned. And these are not the only ones. So put this in your pipe and smoke your own bullshit that you accuse other people of.



Warrior

Which one hit an Elk?

if i could post pictures i woould add some
other "bonded pictures"
of what they look like, what is left anyway after digging them out of elk,deer,moose and bulls.
at 3000 fps 8' from the muzzle.
but warrior posted plenty.
there is a reason that i hold my loads to the velocities i posted.
the bullets work at those velocities.
and i would bet they donot have elk in
zambezi.
but they sure have plenty of other elk sized animals.
when did they get elk in the carolinas?
if i want to load to 3000+ i can i just choose the better route and don't.

Geez guys, c'mon...ENOUGH ALREADY! Just PM each other!
Peter.

Gosh, I can not believe this is still going on.

I thought post No. 2 covered it.