quote:

remember that both test methods have advanced

This is an argument I can except. Also the difference in CUP to PSI conversion not being one to one. I can understand it, that is, if there were blown up guns all over everywhere. Especially with the older non-heat treated cylinders. Except there aren't. So whether you use CUP or PSI or shoot them in an older gun doesn't seem to hold historical water, so to speak. I know there have been guns blown up, don't get me wrong, I'm not saying there haven't been. There are just questions to answer about their condition before firing these types or rounds.

quote:

and the liability atmosphere has worsened.

This is an argument I refuse to accept. I will not allow fear to dictate engineering data. If a certain steel will contain a certain pressure reliably then how in the world can a lawyer change that? Being held hostage in this area "ain't gonna fly" with me any more than someone in a dark alley that wants to take my wallet. I refuse to be intimidated, period. That being said, I can be changed but it is going to take more than one incident, one lawyer, one 'fraidycat to make that happen.

If I want to carry an all steel "J" frame 38spl with a 3" bbl with loads that get 1180fps out of it I will and do. Now, if because of engineering standards/procedures it is proven the firearm was never built to withstand 5 shots with loads like this, I can concede, will concede on that basis. To this point though no one has come forward with conclusive data, no one.


nutty, It isn't "intent on turning" it's more like "intent on returning".

I have ordered a copy of Quickload software and the US distributor is supposed to try and obtain the required data to enter SR4756 powder into the program as this is not apparently a normally included powder.

I was told that the program author does have the data on SR4756 and it should be available.

If obtained I will enter both old and current load data in the program and see what listed pressures are.

I realize that this will be calculated pressure only rather than instrumented information but seeing what the program says should be interesting.

That should be interesting Rich.

As I read the original article this thread is about, I noticed how much the bullet diameter and seating depth affected the end results, regardless of which powder is being used.

Of course, many times we never know exactly what components and seating depth are used in the powder manufacturer's data, which is not the case with specific loads for the proprietary bullets, i.e. Speer's data for a Gold Dot bullet.

Chunkum measured some old Super Vel bullets the last time I was at his house. One of the reasons Lee Jurras could get the velocities he was getting with Super Vel ammo, was the small diameter of the bullets. If you apply 35,000 psi to the base of a properly designed jacketed bullet, it will obturate just like lead bullets do, so bore filling diameter isn't as critical with jacketed bullets.

Paul;

In a lot of the old manuals seating depth or COLs are not listed even for uncannelured bullets as used in rifle and auto pistol data. Certainly true for the Speer #8 data. Newer load data is usually far more detailed regarding providing such info.

Also typically newer powder company data is much more specific about what bullet was used in load development. A lot more specifics in the current Hodgdon manual than in my older hard cover ones.

Another variable I have seen documented with a considerable effect on velocity is neck tension and bullet crimping, particularly with slower pistol powders.

In Gun Notes Ken Waters reported a change of about 50 FPS between identical 2400 loads depending on applied crimp.

quote:

Also typically newer powder company data is much more specific about what bullet was used in load development.

Actually, if one reads the instructions, Speer #8 was pretty specific about OAL. Bullets with a crimping groove were supposed to be crimped there. Jacketed bullets, if one also looks at the picture of the bullets, have a cannelure that's supposed to be used. The half jacket bullets are supposed to be crimped over the top edge of the jacket. It's all in the introductory section to handgun reloading beginning on page 321.

From Sierra #1, 1977 Edition, page 201, dealing with .38 Special.

quote:

The expanding plug of the set should be no greater than .355" in diameter,

That pretty well takes care of the tension aspect.

The Hornady Manual, 1973 edition, specifies seating depth in decimal inches. There are also 6 loads, page 341, .38 Special, that meet or exceed 1100 fps with a 158 gr bullet, seating depth of .341", in the Hornady manual (they used a M14 too).

So, we see that Speer wasn't so outlandish after all. Many of us not only survived those loads, we continue to use them and we use them in the same guns we used back then. Is there a real good reason to discontinue what we've been doing for 35+ years?

quote:

Originally posted by Rich W:

Does any one know if the early Speer transducer test barrels would match current SAAMI specifications as far as transducer location and calibration methods is concerned?

My backfround is as a quality assurance and reliability engineer and this question interests me.

For what it is worth, this article is very similar to the article that Caldwell published in Handloader Magazine, Number 39, Septermber-October 1972, pp 34-39.

I cannot give you a definitive answer to both of your above questions, but if you look at Figures 3 & 4 in the article mentioned earlier, you will see the custom "cylinder" that Caldwell had made up. Note where the centerline of the transducer is. It looks for all the world to me that it is in front of the case mouth, and in fact in the Handloader article Caldwell states specifically that the gas did not impinge on the transducer diaphram until the bullet left the case. The current standard requires that the conformal transducers be located a specific distance behind the base of the standard bullet. For the .38 and the .357 I would assume that that means a 158 gr bullet. The exact distance behind the base of the bullet is a function of which diameter tranducer is being used, and that is determined by the diameter of the bullet. I don't have the info sitting right in front of me, so I cannot tell what those numbers are, but the important thing is that the transducer is supposed to be mounted behind the bullet base and not in front of the case mouth.

By not picking up the pressure until the bullet uncorks the bottle, so to speak, they may have been neasuring a different peak pressure than the current method would. Once you get your copy of Quickload, you will notice that it predicts how far a bullet moves before pressure peaks. With long bullets, it can peak before the bullet leaves the case moouth.

Regarding the calibration, I don't know at this time.

One more item to note is that you need to be a bit careful using things like copyright and publication dates to determine the time sequence of these things. The lead time on something like the Handloader article is roughly 4 to 6 months and for Gun Digest it would be a bit longer since it is only published annually. The lead time for pubishing a loading manual may be on the order of two years, depending on the number of new loads that have to be fired.

For example, if they were following SAAMI requirements, they would have to fire 10 rounds per load level. If you figure that there is a starting load, an ending load and as many a 3, 4 or 5 intemediate steps in between, they may have to fire 50 rounds per cartridge/bullet/powder combination.

If we use the #8 data for example, and for the 158 L-SWC in the .38 Special in particular, earlier manuals had only loads for two powders: 2400 and Unique. At least that is what my #6 shows and I believe that the #7 was the same. The #8 now listed 27 powders. If they re-used the old data and did not refire it, then they would have had to fire 1250 rouds just for that ONE bullet/cartridge combination. If they were using a pressure gun, how many of those 1250 rounds do you think they could prepare and fire in a day? It might take them a week to generate the data for just that one bullet/cartridge combination. In addition to the 27 combinations listed above, ther were an additional 100 bullet/powder combinations, for a total of 127, for the .38 Special alone. If they could fire 25 of those combinations per week, it would take them 5 WEEKS to prep and fire just the .38 Special loads.

When you add in that Caldwell also had to fit in his regular QC duties, I would not be the least bit surprised to find that the #8 data reflected equipement the Speer had in their possession back in 1968, and not what they had in 1970.

Just some not so idle thoughts.

I think Caldwell would have known of the SAAMI specs, since DuPont had been using transducers since at least the 1964 data they published.

I will agree that it seems like the transducer in the custom cylinder is at the case mouth, but that would mean he had to use a different cylinder for .38 Special than what was used for .357 Mag. That seems a little extravagant when one cylinder could have been used for both cartridges.

However, even if it was at the case mouth, it would have still given CIP pressures, which are 9,000 psi higher than SAAMI specs (for .357 Mag).

quote:

Originally posted by Paul5388:
I think Caldwell would have known of the SAAMI specs, since DuPont had been using transducers since at least the 1964 data they published.

Unless you have the documentation to suppport this, I am not sure I buy the argument. And by documentation, I mean a write-up by DuPont of their test set-up. Unfortunately, I have never seen one. But I will give you a bunch of reasons why I question the statement above.

First, as I think I pointed out earlier, until the piezoelectric conformal transducers were in widespread use, people routinely used the dimensions "psi" to refer to the crusher-generated data. Even Phil Sharpe talked about the problem in his big book. If you are assuming that DuPont used the piezoelectric pressure transducers because they used "psi" in their data pamphlets from the '60s, you might be reading way too much into it. Even when people recognized the issue, until the "CUP" and "LUP" descriptors were coined, what choice did they have. They had to use "PSI". Also, if you check out the later DuPont(IMR) loading guides(like my 1989), you will find that pressures are in "CUP", not "PSI". I pulled out my DuPont guides from the mid-70s sometime back, but cannot find them right off, so I don't know how far back Dupont switched over to the use of CUP. However, the fact that their later guides cite pressures in CUP would make me very suspicious that the 1964 data were were measured with the transducers of the day. More than likely, they were using a crusher-based system to generate those data. Why would they go to the trouble to reshoot them with the less reliable crusher method if they already had the data from the better piezo transducers?

Also, the #44 Lyman does not show pressures, but the #45, which has a copyright date of 1970, shows pressures in CUP. So the mid to late 60s seem like the point where CUP was introduced. Or if you will allow me, it occurred to me that there was a succinct way to capture my thought: before a certain date, there was only one way to describe pressure measurements in the small arms internal ballistics world and that was to use the dimension "pounds per square inch".

Second, the life expectancy of the early transducers were measured in just TENS of shots. Caldwell mentioned in the Handloader article one transduer that lasted only 60 rounds. When they first came out they were very expensive and short lived which made them tools for major ballistic labs. I would expect that they would be confined to cases where they only needed one or two major experiments per week, not a couple of hundred rounds per day.

Third, I will grant that DuPont certainly qualified as a major ballistics lab, so they easily could have had the piezoelectric transducers and probably did. But that doesn't imply that a standard existed at the time. I don't know how much exposure you have had to standards generating organizations, but back in the 1980s I worked for a consultant to the major theme parks. We did safety testing for their coaster-based rides, and used his proprietary equipment to get the data. We used his equipment for more than a decade before ASTM even put a committee together to establish a standerd for such testing. The point is that because testing equipment is in use, it does not imply that a standard exists. Oftentimes, standards are generated because the data from various test methods in use cannot be reconciled easily.

quote:

I will agree that it seems like the transducer in the custom cylinder is at the case mouth, but that would mean he had to use a different cylinder for .38 Special than what was used for .357 Mag. That seems a little extravagant when one cylinder could have been used for both cartridges.)

I don't know what you are trying to get at here. They did make two cylinders according to the Handloader article, one for a K-38 and a second for a Model 27. What is more, the transducers weren't of the conformal type where they form part of the chamber wall as currently used. Caldwell stated that they drilled a 1/16 inch port just in front of the case mouth to vent some of the gas off and direct it to the transducer.

quote:

However, even if it was at the case mouth, it would have still given CIP pressures, which are 9,000 psi higher than SAAMI specs (for .357 Mag).

I am not certain what you are trying to say here. I don't know what the significance of the CIP pressures are relative to the data collected back in 1970 at Speer.

And there is some technical confusion here, as well. For both rifle and handgun cartridges, CIP requires a pressure port drilled somewhere into the chamber wall to expose the transducer to the gas pressure. However, the use of a transducer mounted in front of the case mouth is only for RIFLE cartridges according to the CIP description given by Vihtavouri. For handguns, the measurement is made over the case body, but unlike SAAMI's use of conformal transducers which don't require any special processing of the cases, CIP requires a hole drilled in the case at the location of the pressure port.

So if we assume that the CIP standard hasn't changed fundamentally over the years, then Caldwell could have been measuring pressures in a way that no one else was at the time.

Also, without copies of the older versions of the standards, we don't know what was really required or how the testing has changed over the years.

This message has been edited. Last edited by: Mack Heath,

BTT

Mack,

I've been digesting on your post somewhat while I've had company over the weekend.

I have previously posted the U. of Michigan paper, published in 1965, that was part of a grant from DuPont. The paper indicates all of the major powder manufacturers were already using transducers with the exception of 5 or 6 who were using strain gauges. DuPont was certainly a major powder manufacturer in 1965. The 1964 data from DuPont was taken with transducers, regardless of what they reported later.

quote:

Under C.I.P. proof test standards a drilled case is used and the piezo measuring device (transducer) will be positioned at a distance of 25 mm from the breech face when the length of the cartridge case permits that, including limits. When the length of the cartridge case is to short, pressure measurement will take place at a cartridge specific defined shorter distance from the breech face depending on the dimensions of the case.

Under SAAMI proof test procedures, for bottlenecked cases the centre of the transducer is located 0.175 in behind the shoulder of the case for large diameter (0.250 in) transducers and 0.150 in for small diameter (0.194 in) transducers. For straight cases the centre of the transducer is located one-half of the transducer diameter plus 0.005 in behind the base of the seated bullet. Small transducers are used when the case diameter at the point of measurement is less than 0.35 in.

Figure 2. The flat diaphragm quartz type pressure sensor can be installed either in the drilled case location (A) or the case mouth location (B). Both installations involve gas passages that affect the operation of the test barrel and therefore the measurement process.

quote:

Quartz Sensors. Ballistic quartz pressure sensors have been used since the mid-1960s in both research and production testing for measurement of ammunition and gun barrel pressures. These sensors are installed at either a case mouth location or over a drilled cartridge and measure gas pressure directly from the burning powder (see Figure 2). One advantage of this method is that a single sensor can be moved from barrel to barrel to fit a machined recessed mounting port in a variety of calibers. However, both case mouth and drilled cartridge installations have inherent limitations, especially with the gas passages associated with recessed mounting.

To protect the quartz sensor from flash thermal effects, an ablative diaphragm coating must be applied and frequently replaced. Another disadvantage is that the recessed mounting port affects the operation of both the gun and the gas dynamics of the measurement process. With smaller caliber ammunition, such as .22, .38, and 9 mm, the sensor's recessed mounting port adds significantly to the volume inside the cartridge and always results in lower pressure readings [1]. Furthermore, the gas passage in front of the sensor may become restricted or plugged and require frequent cleaning. Sensor Magazine 1999

In 1999, according to Sensor Magazine, the conformal transducer was an optional method, not the primary method.

It appears Caldwell was using the standard procedure of positioning the transducer 1/2 the sensor diameter plus .005" below the seated bullet. That would necessitate two cylinders for the revolver he used.

quote:

Originally posted by Paul5388:
Mack,

I've been digesting on your post somewhat while I've had company over the weekend.

I have previously posted the U. of Michigan paper, published in 1965, that was part of a grant from DuPont. The paper indicates all of the major powder manufacturers were already using transducers with the exception of 5 or 6 who were using strain gauges. DuPont was certainly a major powder manufacturer in 1965. The 1964 data from DuPont was taken with transducers, regardless of what they reported later.

Paul,

A couple of points to address. First, thanks for the link to that report. That was the #1 report that Brownell talked about. I tried to get a copy of it back around 1980-1983 from Ulrich's. At that time, they confirmed that they had had a master of the report at one time, but could not find it any longer. They still had a copy of the #2 report that Brownell produced, and I managed to get a copy of it. There was a rumor that a third report was supposed to be made available. Brownell mentioned the #3 in some of his writings, but Ulrich's never saw it. At least not according to the person I spoke with.

Second, I still have reservations about your last sentence above, though. Do you have some other documentation to indicate DuPont confirming that they actually used the piezoelectric transducers to collect the data? One piece of info you provided showed that DuPont stopped providing pressure data for handloaders from the '30s until 1962. If '62 was the original issuing date, then the '64 data most likely were just the same data re-issued. The DuPont manuals that I have over a number of years tend to confirm that practice. Again, as I said earlier, I find it hard to believe that DuPont would have re-shot all of those loads using the older crusher system if they already had them using the more accurate piezo system. Even if the protocol that they used with the piezo system was outmoded by later conventions, I would still have expected them to reshoot the loads with the most modern methodology, meaning the newer piezo protocol.

quote:

Originally posted by Paul5388:

It appears Caldwell was using the standard procedure of positioning the transducer 1/2 the sensor diameter plus .005" below the seated bullet. That would necessitate two cylinders for the revolver he used.

The above statement I think is inverted. I said that Caldwell did produce two cylinders, but that he specifically stated that they drilled 1/16" pressure ports just in front of the case mouths.

Ports in front of the case mouths would, I expect, give lower pressure readings as the bullet base would have to clear the case mouth before the gas could reach the sensor.

No idea what the difference would be but with fast burning powders it could be considerable I would think.

Newer equipment used in testing of later loads, plus a decision to not continue listing "high speed" 38-44 loading data, could well explain the drop in powder quantities recommended in later manual editions.

Looking at older manual data I find it curious that there is no note I have seen stating that the maximum load data for 38 special ammo is intended as 38-44 high speed load data but based on factory high speed ammo ballistics claimed it almost has to be.

Mack,

I don't remember reading that portion about the transducers being in front of the case mouth. However, the link I provided from Sensors Magazine seems to indicate both positions can be used. Again, that may just be a concession to the NATO protocol that uses the case mouth position.

By using this link http://deepblue.lib.umich.edu/handle/2027.42/3866, you can access the original Brownell paper, but any succeeding papers should also be available through the search function on the link. The PDF format is much better than the text format, since you can see all of the charts and graphs.

Rich,

If you read the introductory comments for the 2" loads, it will tell you what guns the loads could be used in and none were .38-44s. BTW, this is Speer #8, 2nd Edition data.

Paul;

That is the same note as in the first edition however there are no such warnings or use notes in the main 38 Special section. To me that is the one most reloaders would read.

May be inappropriate on a S&W group but I worry about all of the old, and not so old, foreign made 38 Special revolvers floating around out there. Guns from Spain, old Belgian stuff etc. Per my understanding some of the old guns from such sources were of questionable strength even when new.

Even old pre WWI Smiths in 38 Special could, I suspect, be possible subjects for failure if pushed too hard.

I have read of several instances of old 38 S&W chambered break top guns from S&W, H&R and Iver Johnson being blown up with standard listed reloads from older manuals. The same for some imported guns in this caliber.

The S&W break top was even made up to the start of WWII but I have seen recommendations that all break tops except the Enfield and Webley guns be limited to black powder loads.

Maybe I am too conservative but I would hate to see someone destroy a gun or injure themself due to loading ammo inappropriate for the strength of a older gun.

Reloads people choose to use are their own choice but without knowledge of the actual strength of a given gun I tend torwards the conservative approach.

Just to pass on a thought about the "sudden" appearance of CUP labels on pressures at a specific time.

Could this be the time frame at which it became apparent that CUP pressures were not, in fact, the same as PSI?