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Discussion Starter #61
In most revolvers you will get sticking cases long before you get a flat primer.
The only sure way that I know of to know you are over pressure, and this is cartridge specific, is sticky cases or primer pockets getting loose in less than twenty reloads.
I have not run into either of these situations with the loads I have used in my Ruger 357's.
The recoil is "normal" to me with a notable muzzle blast and sharp recoil. I don't try to control it, rather let the gun recoil in my hand and there is no shock to my hand, arm, and shoulder. With a warning that my load exceeds the maximum load in most manuals but not in all I will share this information:
Remington case trimmed to 1.285, CCI550 primer, 19.5 gr. of H110, Sierra 140 gr. JHC seated to an overall length of 1.590, with a heavy roll crimp. I get an average muzzle velocity of 1599.12, Extreme spread of 24, Std. Dev. of 7. My average aggregate group (4 x 5 shots for 20 shots) is 1.35 at 25 yards. The average five shot group is just under 1" at 9.04" at 25 yards. Velocity and related data taken with a LabRadar chronograph.
The brass falls out of the chambers under its own weight and the cases get reloaded until the neck splits. I put well over 30000 of these rounds through my now 48 year old Security-Six and it still shoots the same size groups it did when I was competing with it in Hunter's Pistol Silhouette. It has never been to a smith for any repairs or tuning.
I don't believe that these loads are any concern in a modern 357 magnum.
 

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The Hog Whisperer (Administrator)
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All,

A lot of good information in a long thread. And, like all discussions some information is not so good. One thing I don't believe was mentioned (and I could have overlooked it) is that many/most powders made today are not identical to powders made 20, 30, and 40 years ago. So load data will change as the powders change. I believe Clays is a good example. Current manufacture Clays differs from older Clays and there are cautions to use current load data for Clays not older manuals.

I don't see how anyone can argue current measurement methods for chamber pressure are not better than the older CUP method. Yes, there are differences in how C.I.P. and SAAMI develop their standards for ammunition, and how they measure pressures are different. A case of beer discussing the pros and cons of each will only result in a case of beer being consumed and no agreement on which is better.

Regardless, Paul's comments are valid. While CUP measurements have limitation and accuracy issues they were a usable measurement method for decades. The difference between 45,000 and 33,000 CUP is 36% in whole numbers. Why did the SAAMI numbers for 9mm and .357 Mag change to 35,000 psi for in 2015 when their CUP pressures were 36% different? My belief is not entirely because of the change from CUP to psi measurements.

The real question is why the change and are published loads from decades ago still safe today. C.I.P. data leads me to beileve they may be. But, the real proof is testing, in Paul's case, H110 from he started using that load years ago to the powder he is shooting today.

Powder manufactures work hard to ensure new manufacture powder is consistent with older versions of the same powder. But manufacturing locations, equipment, and techniques do change and it does change how the powder performs.
But it is worse than you think. If the futility of comparing CUP to PSI isn't enough, there's the futility of comparing CUP to CUP. Huh? See Nick's writeup of .30 carbine testing via CUP, where 9 different labs ended up with a spread of 23% for the same lot of reference ammo. So, are you comparing 45,000CUP to 33,000CUP, or are you comparing something in the range of 40,000 - 50,000CUP, to something in the range of 29,000 - 37,000CUP? One of them is pretty close.... the other way far off.

That's the problem with an inaccurate / inconsistent measuring system like CUP; no one really has any idea of what they are getting, and it isn't repeatable between two properly equipped, trained facilities. If they can't do it, there is no hope for the rest of us.

You can't rely on data from inconsistent measuring systems. Hope the quality control engineer that helped build the next airplane you ride on, was paying attention in statistics class ;)
 

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I set up a set of three pressure barrels for Barber Ammunition in about 1979. SAAMI specifies (or did), exactly the diameter, tolerances and location of the vent hole and sets all the parameters. Copper slugs are made for the industry for a variety of uses in measuring direct pressure and are certified to compress a given amount for a given pressure, but the scale is algorithmic and deals in fifty millionths accuracy in measurements (.00005") Lance Weber (owner at the time), ran pressure test on every lot and kept the slugs on file.

I worry about the primer!! That's the weak link in the chain and the most likely to hurt you, but there are many warning signs that link is getting close to failing, LONG before you get there. It's important to know the signs, know how to 'read' the signs, and know enough to back off when the signs become serious. If you need to put a NUMBER on 'serious' that's fine, but then you're a slave to what it tells you. Observations of real conditions is my preference. "The primer is leaking". No matter the number, something WRONG. Fix it.

Guys lie about fish, girlfriends, gas mileage and velocity of wildcats. It's just in our nature. :)

PRESSURE gives us velocity and too much gives glass eyes.
Lack of velocity is a great excuse to buy another rifle!
 

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So how good is the Pressure Trace? Now giving serious thought to ordering one. I "assume" it would have to be used on a rifle chamber, rather than a revolver's cylinder.

I subscribe to the Linebaugh school of thought that so-called "pressure signs" are meaningless in a straight wall revolver cartridge. That is a bottlenecked rifle phenomenon. Revolvers can show no signs at all before blowing and sticky extraction is usually something else entirely.
 

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The Shadow (Super Mod)
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So how good is the Pressure Trace? .
Remember "garbage in = garbage out".
If you want generalities, and somewhere under 10,000 psi, then chop a piece of brass apart and do some measuring, ask for a pressure number from an ammo makers for a lot.
If you want to be VERY close, cast your chamber and carefully measure; then Order some reference ammo.
Just depends on how much you want out of it.

An honest caution:

Be prepared to have A TON more questions when you start using it, than you had prior to using it. There is literally mountains of truly bad info out there, and lots of things that you presumed or read more into than you should have.
Signs and burning speeds were my biggest mistakes. I thought I understood what was happening, until that first string and watching what the burning curves were actually doing.:eek:
 

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In THEORY all CUP measurements done to a specific Test Specuification using equipment manufactured to that specification's dimensions and tolerances should be repeatible and consistant in results.

In PRACTICE CUP testing is NOT repeatable within 23 percent between test labs supposedly using the SAME Test specification!

I am hoping the testing repeat-ability of piezoelectric sensors is much better than CUP but I have not seen information on that question.

Strain gauge measurements are also subject to errors and lack of repeat-ability, alxs to percentages not yet discussed.

I know from experience that there are Many sources of error in every measurement system and Test Specification.
The better ones try to reduce the error occurrences to a minimum and to get most of the residual errors to 'cancel each other out'.

In my opinion, all factory test information is mildly suspect and is only as good as the integrity of the corporations and people performing and reporting the information, with the 'weakest link' being the least reputable of the entitles handling the test results reporting.

Chev. William
 

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The Shadow (Super Mod)
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I am hoping the testing repeat-ability of piezoelectric sensors is much better than CUP but I have not seen information on that question.

Strain gauge measurements are also subject to errors and lack of repeat-ability, alxso to percentages not yet discussed.

Then you've ignored some great information that's been right under your nose the whole time.:)

Piezo/Cup was covered in this thread, post #27 contains a link to a thread by UncleNick, that was done a few years after your join date. The accuracy of strain gauges have been covered in several threads in the past 6 months alone.

Dr. Denton Bramwell who was still active when you joined, has some stickies and many wonderful threads and links to his articles; has covered this many times. Use the search function, pick up your old copies of Varmint Hunter magazine, or go to RSI's website where they have many good links, including to some of his technical articles.
Similarly SAAMI'S website has loads of wonderful information about this subject. Turns out that site is good for things besides cherry picking data for a conspiracy theory.

Cheers
 

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I retired from a city as PD Armorer and shop super working on cop cars. For 21 years I had my own 200 yard range near Rising Star Texas, and shot a lot of 357 magnums. I don't really care if SAAMI, PSI, CUP, Moon phases or what is used to test pressures, VELOCITY did drop from what was originally loaded...at least according to my tests 10' from the muzzle. Much like 30-06 ammo being loaded for old 1906 guns, the industry MUST avoid legal attacks from the left. My 30-06 is a 1990's Remington that can handle hotter loads and likes 165 grain bullets at about 2800 FPS. I am 76 and "accurate" to me is 5 shots at 100 yards I can cover with my fist. My 06 can do that if I do my part. I am a big fan of the 357 and have what I call my 357 SET. It is a Rossi 92 short barrel lever gun and a Taurus 669 revolver 6" barrel. Either works great on hogs...and Javelina at Terlingua, Texas where my brother has land. If you have ever jumped into a dry river bed and been charged by a wild hog, the quick into action handgun makes lots of sense, even if not a handgun hunter. At my age long shots over 300 yards, are not taken, even with the 30-06. Hogs became a serious problem on my farm, and though I was told a 357 was not enough gun, many a dead hog would disagree.
 

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Then you've ignored some great information that's been right under your nose the whole time.:)

Piezo/Cup was covered in this thread, post #27 contains a link to a thread by UncleNick, that was done a few years after your join date. The accuracy of strain gauges have been covered in several threads in the past 6 months alone.

Dr. Denton Bramwell who was still active when you joined, has some stickies and many wonderful threads and links to his articles; has covered this many times. Use the search function, pick up your old copies of Varmint Hunter magazine, or go to RSI's website where they have many good links, including to some of his technical articles.
Similarly SAAMI'S website has loads of wonderful information about this subject. Turns out that site is good for things besides cherry picking data for a conspiracy theory.

Cheers
I reread the refered to post and the linked post. it does show a improvement in reputability between Piezo and Strain gauge based measurements over CUP, but also indicates agreement that there are still errors in the results that are addressed to varying degrees by individual test labs.

As indicated, sample size is also a way to improve accuracy of the reported results, with larger sample sizes 'capturing ' more possible variations to be taken into account.

With both piezo and Strain Gauge measurements there are also improvements slowly being made in the measurement system components over time that is also a factor in accuracy comparisons, both to data reported by a given lab over time an dto variations in reported data between labs.

one point example: the instrument response 'bandwidth' of the indicating system, such as a computer or visual display or recorder. if it is of low bandwidth the data will not have accurate reports of the peakes of pressure spiking. as the .bandwidth' is increased the pressure spikes will be shown more accurately , but is a given 'bandwidth' sufficient? Or is a greater 'bandwidth' needed for more accuracy?

Similar factors should be considered for each piece of equipment in the measurement system chain of processing the RAW instantaneous information through to the final displayed result.

In my working lifetime 'bandwidth' of measuring instruments went from 10 kilohertz tho several gigahertz in some laboratory quality equipment, with prices going up with each improvement. For single event instantaneous the actual measurement chain 'bandwidth' is stil down inthe 'Megahertz reange due to some material physics. Labs are still working to refine and improve those limits but it is still a problem as far as i know.

What I am trying to say is that CURRENT and PAST reported information may not be directly comparable due to limitations tha texist or did exist on the measurement system used at the time, and is still not an "accurate' exact report of true existing conditions.

Even my own personal experiments have built in errors due to the conditions i have to live with.

Chev. William
.
 

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The Shadow (Super Mod)
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I don't really care if SAAMI, PSI, CUP, Moon phases or what is used to test pressures, VELOCITY did drop from what was originally loaded...at least according to my tests 10' from the muzzle. Much like 30-06 ammo being loaded for old 1906 guns, the industry MUST avoid legal attacks from the left.

The "Left" may or may not want to limit various things, but they aren't the single lurking mover behind load info. You said you were an armorer. If you did some modifications to a trigger that you thought was safe and reliable, but sometime later learned it was not safe and could be dangerous. If you quit modifying triggers in that manner, because you're a reasonable person and didn't want to cause harm to anyone; would it be reasonable to say:
The Left "got to you"?
How about because the Kabal didn't like you making them look bad? :rolleyes:

There are lots of reasons why factory ammo may have lower velocities, not least of which is far better testing resolution and understanding of pressure. All of which has been discussed in this thread, including a great link to one of Nick's great explanatory posts that many refuse to read; or the actual data explaining this l that she info on the SAAMI website.

So here's another link for folks to ignore, with an example where the lawyer argument holds a contraction. Post #65

https://www.shootersforum.com/handloading-procedures-practices/21362-saami-pressure-chart-4.html
 

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The Shadow (Super Mod)
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I

What I am trying to say is that CURRENT and PAST reported information may not be directly comparable due to limitations tha texist or did exist on the measurement system used at the time, and is still not an "accurate' exact report of true existing conditions.
.
Current methods (piezo/strain) are an accurate reporter, but they certainly aren't an absolute recorder. I think we can all agree that by definition, we can never honestly be absolutely certain of very much if anything.;)


If you'd like to read about testing and bandwidth limits, there are some very good outside articles here:
https://www.shootingsoftware.com/tech.htm

Cheers
 

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One thing I have noticed is that powder charges have dropped in the loading manuals for certain rounds. Most noticeable is the 357 Magnum. Velocities are also less. Why? Might be better testing equipment that may show pressure spikes more accurately.
 

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Discussion Starter #73
Well, the European loads are still up where the original loads were here in the states. The loads here in the states have been reduced. If you want to know why take your medium frame Smith or Colt and fire my reloads in them for a few cylinder loads. Bring your screw driver set to retighten the side plates. ;)
 

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Elk Whisperer (Super Moderator)
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take your medium frame Smith or Colt and fire my reloads in them for a few cylinder loads. Bring your screw driver set to retighten the side plates. ;)
Maybe it's just me, but I don't think I'd fire YOUR reloads in YOUR revolver.

Advocating unsafe acts is not how we roll here, uhmkay?

RJ
 
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Discussion Starter #75
I would not ask you to fire my loads in any gun.
The "unsafe act" is a bit overboard for a load listed in at least two manuals.
I will drop it there and play nice.
 

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Elk Whisperer (Super Moderator)
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Powders change with every lot. I've noticed this with both H110 and 2400. My loads from thirty years ago are much "warmer" if I load grain for grain, not to mention Dad's loads from 50 years ago.

RJ
 
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Discussion Starter #77
I called, early on to check if the powder had been changed and was assured the powder was the same.
Yes, I understand lot to lot differences but that has little to do with the change in loads. Back in the early 70's Winchester stated that their 16.6 load of 296 with a 158 gr bullet should never be reduced or increased due to possible pressure fluctuations. Yet the loads today range from starting loads as low as 13.2 and a high of only 14.7 while other sources go as high as 17.3 with the same bullet.
Now there are many differences in all the different manuals because of the many variables in reloading so YOU must decide what load is right for your gun. Always start at the low end and work the load up gradually while being mindful of signs of excessive pressures. In revolvers the first sign is typically sticky cases. That is not always a good indication and neither are flattened primers so you have to be cautious in your approach.
Winchester never listed a load for 140 grain bullets but Speer and other manuals did. And I watched as the maximum loads dropped and I contacted the folks who put the data out asking why the change. Several noted that their loads were within the SAAMI recommended loads. When I asked about older data I was told that the specifications had changed. I was never given a reason until I contacted one Bullet manufacturer and was told that their data was based on the tests they did using the original SAAMI specs and they refused to drop them for political reasons when the loads were still just as safe as they were before.
 

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Elk Whisperer (Super Moderator)
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With all due respect, maybe you can explain the velocity and obvious pressure differences between grain for grain loads with the same bullet (158gr XTP and 240 XTP respectively) in both .357's (i have three) and 44 magnums ( I have two) with data from 1977 (Lyman 45th) and new data (Hodgdon online and Alliant on line)

RJ
 

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The Shadow (Super Mod)
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I called, early on to check if the powder had been changed and was assured the powder was the same.
Yes, I understand lot to lot differences but that has little to do with the change in loads. .
You asked a used car salesman if the car you're looking at is "a good deal", once he told you yes, you believed him.:D:D:D

Clearly you don't understand the powder world

Hodgdon may buy current production powders or surplus, such as WC846. Which has "the same" name for the past 83 years. The name commonality is the only thing that's "the same". Funny enough, Hodgdon made a very good living for a few decades selling surplussed 846 lots from inception to the them current stuff. None of it was "the same" but guess what, he kept the name the same.....

What you call IMR4064 has had two very different parent powder sources in the past 2 years, yet they changed no data, no names were adjusted, and short of legally required packaging changes didn't plan on saying a thing about it.
They buy powder based on general burning rate ranges, and some attributes. As long as they can buy or blend it somewhere into that range its fine.

The reloader just doesn't use very much powder, in the scheme of things. They demand data for a stupid number of cartridges, many of which will never actually buy enough powder to fire more than 200 rounds in their lifetime, and they ask for this data from companies who are... What's the polite phrasing.... "Re-purposing" or are the kids calling it "Up-cycling" gunpowder :rolleyes:
The painful truth is that market doesn't justify pressure testing every cartridge even annually, regardless of changes. But it's cheap and easy enough to run it through a calculator based on fixed volume bomb calorimeter testing, which gives an APPROXIMATE burning rate.

That doesn't tell you what a powder actually is, or scale to reality in many cases.
I've had dozens of phone calls and email back and forth with Hodgy over Superformance in the Creedmoor. They'll tell you it's not useful, and in fact is dangerous due to how slow it is.

Now it's true that if all you use is a simple calculator based on the burning rate charts, it's not a good choice. It's also true that when using bronze age tools such as copper crushers as they do; that you can't even begin to understand what is going on. So again, using that powder may seem scary.
But when you actually talk to the man who created and tested it, who uses modern equipment to test and observe; well that powder has a very beautiful fit in the Creedmoor. When I stepped up into real pressure testing, I can confirm it.
Despite what Hodgdon's minions get told to say.

Cheers
 
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