Home Forums Hunting & Shooting Ask The Gunwriters Load differences in newer manual

working on idea for making some new 357 Magnum loads some in rifle some in pistol. long story short :
I have four different editions of Hornady manuals 3, 6, 9 and 10.
6, 9 and 10 have identical data for. 357;
if the old #3: has much different data most of it is significantly higher powder charges of the same powder.
now is that because powder formulas change through that time period 3 to 6 powders changed , bullet anatomy changed or lawyers changed?

None of the above.

Measurement systems got better, and some of the old loads were hotter than we thought they were.

and I take it you don't mean scales and such you mean lab equipment to measure actual pressures?

That's exactly what Denton means--and is also the major point of Chapter 16 of my book Rifle Trouble-Shooting and Handloading, which was published over a decade ago.

One of the things that's always interested me is how many handloaders don't do much recent research on such subjects. Instead they keep being puzzled about the difference in older and newer data--IF they go that far.

As I explain in RTS&HL (which obviously isn't very recent), older manuals not only used less accurate pressure-testing systems, but bullets varied a LOT less back then. Almost all rifle bullets were cup-and-cores, which did tend to result in similar pressures, no matter the brand. This is why the older Hodgdon manuals (and most others) listed a basic bullet weight-range of loading data for a particular cartridge.

Today we have bullets made out of all sorts of materials--each of which results in different pressures.

Exactly.

In the early days, Speer was using micrometer measurements of case head expansion. That approach is now not looked on with favor, at all.

For a long time, copper crushers were the usual choice. Those were thought to give results in actual PSI. And on the low end of the scale, they were pretty close. On the high end, what we thought was 50 KPSI turned out to be about 62 KPSI. Big shock! Plus, the copper crusher system suffered from mediocre repeatability.

Piezoelectric and strain gauge systems are what we use now. In the 1960s, vacuum tube based systems were capable of doing a good job with those systems, but the shift to solid state equipment made it all much better and more portable. These systems give results in actual PSI, with respectable repeatability.

Our pressure measuring equipment is far better than that of a few decades ago. And some of the old loads are not what we thought they were.

are the velocities and some of the manuals estimated from pressure then? cuz I noticed the examples I was looking at tonight the older one the velocities were noticeably higher per weight charge not even including the max loads.

I don't know for sure.

What I do know is that even in the early days, we had ballistic pendulums to measure bullet momentum. From that, it's easy to calculate bullet speed. I suspect that is what they used.

I don't know for sure either. I do believe that reports of lawyer forced changes are flat wrong. In some cartridges as for instance the 7mm Remington Magnum, experience has shown a disturbing number of pressure excursions and so average pressures have been reduced to reduce the impact of pressure excursions although the previous intended average pressure was acceptable the ceiling with pressure excursions from the previous average was unacceptable. Then again just as reported ballistic coefficients have sometimes been maybe rounded up for marketing some other reported figures may give the benefit of the doubt to marketing.

As I recall Jack O'Connor reported using a Potter Counter Chronograph belonging to Vernon Speer - maybe a $5000 investment? Lots of discussion of chronographs in successive editions of Phil Sharpe's book. I've never heard the truth about what happened when the Speer people asked Mr. O'Connor for his key to the lab. Rumor says the Speer plant wasn't happy with results using copper units of pressure for whatever reason, maybe inconsistent test conditions depending on weather there along the Snake? so kept using case head expansion even when Speer could have done better. On the whole I'm just as happy the Speers, Fred Huntingdon, John Nosler and Joyce Hornady got their respective businesses going in somewhat easier times.

Just to muddy the water, I do believe at one time Speer used case head expansion measurements as a proxy for pressure but I believe for a while they used house built jigs with dial indicators rather than micrometers and so got better measurements though with no more information.

Similarly in the case of .357 Remington Magnum loads in the copper crusher days speeds may have been measured and published as fired from the pressure barrels. As I recall it was a big deal when the lab moved to vented pressure barrels for revolver cartridges. IIRC it was claimed to more accurately predict customer's results. It's a certainty that over time some data books reported as fired from pressure barrels and others - even the same books with different cartridges - reported as fired from common firearms after workup in pressure barrels. Reports differ as to whether pressure barrels tended to tighter bores and chambers and so developed higher pressures than common firearms. Certainly not vented and almost invariably different lengths than used in the field, maybe shorter than a long rifle barrel and longer than a short handgun barrel to suit universal receivers in the ballistics lab so not the same numbers as produced in the field by users who not only didn't do the SAAMI twist to position powder maybe never heard of it. Not a book load but IIRC Ken Oehler has some amusing tales of a load in .357 Remington Magnum cases that was supersonic with the powder back and subsonic with the powder forward.

Bottom line, there's no gain from treating data books as holy scripture and less to be gained from fighting over doctrinal points like early Church Fathers quoting Matthew 5:18 on one iota of difference. Just the same is gun is dangerous.

Final unasked for advice. Buy the latest data book. For Hornady it's number eleven in print and early access to data for in work number 12 is for sale by Hornady for access on a smart phone application.

Regarding load data for the 7mm Remington Magnum per the ClarkEMyers post...

I only started loading for this cartridge about six or eight years ago. The discrepancy in load data from the old books (of which I have many) in comparison with the new ones is considerably greater than with any other cartridges I'm aware of and I've been handloading since 1965. Maybe some here are aware of similar big variances in load data with other cartridges.

Max loads for the 243 Winchester have been reduced as well. Like the 7mm Remington magnum, the 243 has been found to exhibit more shot to shot pressure variability than a lot of other cartridges. So the loads for these two have been reduced to slide the probability distribution of pressures toward the lower side of the pressure axis. This means less of the upper tail of the distribution is above the no-go level, so in shooting you're less likely to catch a high side outlier.

I totally agree about the pressure testing improvements & new bullets.

And would like to add that there are, at times powder changes as well. For instance, 2400. The OP doesn't mention that powder, but it is a popular magnum pistol powder & it did change a bit a few decades ago.
This is reason enough to buy a new & updated manual every now & then.

My great pleasure was Nosler #5, 58.5 grains IMR7828 pushing a 160 grain partition to 2942 fps in 280 Remington... their online data reduces it to 54.5 grains and 2751 fps... !!!

Wtfo!! Bummed in Virginia...

You beat me to it. I'm not understanding the reduction in max charges though. Probably missed a memo somewhere down the line. I've always been under the impression that the .243 and 7MM Rem. Mags had excursion problems due to people doing to light a charge with slow burners like 4350 and 4831. We all understand using too much powder but it was the problems with those seeking a light load getting abnormally high pressures that proved confusing. I forget whether it was HANDLOADER or RIFLE that had an article by a Roy Smith. Being a cautious type he went below the starting load for one of the 4350s as I recall and experience very high pressure that caused damage to his rifle. An interesting read BTW.

FWIW, Mr. Smith wrote several articles and developed the .338-08 that apparently became the .338 Federal. Dunno if he was the first of one of many. he was an entertaining writer. Opinionated as hell but I thought he was good. He passed away quite a few years ago.
PJ

I'm not talking about light charges with slow burners causing major excursions.

The ordinary max charges are reduced to slide the pressure probability distribution lower on the pressure axis so there's less probability lying beyond the too much level in the high side tail of said distribution.

Gotta love the Nosler #5. Fortunate to also have a 280 Remington. This is the data set to use..for me anyways. Newer data is getting pathetically cautious. Litegated away any hopes of being useful