Load Data

[John R]

I have some load books that are 20 yo 30 years old, and also some very new ones.
I've noticed over the years the loads for the same powder and bullets are reduced from what they once were, are the powders that much more efficient, or have the lawyers just gotten involved now?

For instance the 357 magnum loads of today seem like cream puffs compared to what they were 25 years ago.

[MichiganScott]

Measuring pressure is much more scientific today than it was 20-30 years ago. Some of the reloading companies used to figure max loads like we do. i.e., primer appearance, bolt lift, etc. Others used lead or copper crusher gauges.

Today, they use piezoelectric gauges and strain gauges. Copper and lead units of pressure all depended on who was running the test.

[John R]

Thought I posted this in the reloading section, oh well.

[alwslate]

For whatever reasons, maybe new smaller and lighter guns, the
maximum pressure standards have been lowered for the .357 mag
and .44 mag. Don't know about the .41. Thats the main reason the
load data has been revised downward in the loading manuals.

[rwsmith]

Better testing and all the other stuff is true.

But I think that about everything is wimpier than it used to be. We used to play with M-80s and Cherry Bombs. Muscle cars were common. Candy bars were bigger.

Wimpy, wimpy, wimpy.

[Alk8944]

Originally Posted by alwslate

For whatever reasons, maybe new smaller and lighter guns, the
maximum pressure standards have been lowered for the .357 mag
and .44 mag. Don't know about the .41. Thats the main reason the
load data has been revised downward in the loading manuals.

You fall into the same error that many make, looking at numbers without knowing what they represent! The old pressure standard for .357 and .44 Magnums was ca. 45,000 PSI, as determined by Copper crusher equipment. This is now referred to as Copper Units of Pressure or C.U.P. The new pressure standard is ca. 35,000 PSI Absolute, or PSIG(uage). The difference is the measurement method. While the numbers are different they both represent the same Maximum Average Pressure for the respective method. If you were to test the same lot of ammunition in side-by-side tests, using each method, you would see results with approximately this same spread. If you were to read a good re-loading manual you would find this explained!

[alwslate]

Originally Posted by Alk8944

You fall into the same error that many make, looking at numbers without knowing what they represent! The old pressure standard for .357 and .44 Magnums was ca. 45,000 PSI, as determined by Copper crusher equipment. This is now referred to as Copper Units of Pressure or C.U.P. The new pressure standard is ca. 35,000 PSI Absolute, or PSIG(uage). The difference is the measurement method. While the numbers are different they both represent the same Maximum Average Pressure for the respective method. If you were to test the same lot of ammunition in side-by-side tests, using each method, you would see results with approximately this same spread. If you were to read a good re-loading manual you would find this explained!

Ok, first of all I have numerous reloading manuals and I do
read them beyond the load tables, do you? And I have read
many times about the different ways of testing pressure and
know that the relationship between C.U.P. and PSI differs
between different calibers and that there is no formula that
can be readily applied to all cartridges to determine one
value from another. The old standard for the 357 was 46,000
C.U.P. and the 44 was 42,000 C.U.P. as I recall. The new
standard is 35,000 PSI for the 357 and 36,000 PSI for the 44.
If you presume to know the exact relationship between the
new and old values and how to exactly derive one from the
other please share it here. If you really read your manuals
you would also know that part of the difference in testing
procedure is the different location on the case the two
methods take reading. Maybe you fall into the same error
that many make in assuming that you know all the answers
when it comes to reloading.

[David R]

I remember some things changing. First of all, we are using the same guns as in the 70s. SO loads from then still are ok with me. I remember when 4 grains Bullseye and 5 grains unique was a standard for 38 specical 158 lead bullet. It worked then, and it works now for ME. you do as you wish.

I still consult the lyman 46 and even have speer #8 so I know what NOT to do. A chronograph is a good thing in the situation mentioned in the first post.

I read all the data I can find and go from there. Common sense, a chronograph and time will make for good safe loads.

David

[Biggfoot44]

Yes , modern pizoelectric equipment is more accurate.

Yes , in at least some instances more sophisticated statistical analysis of test data is performed.

And still yes , the above factors in at least some instances resulted in greater circumspection of published data.

And even further Yes , Pizo (psi) readings are different critters from crusher ( CUP, LUP ) reading , there is no consistant relationship, much less a conversion factor.

BUT !!! There is (at least) one instance where my skepticism kicks in , specifically in regards to .357 Mag , when viewed in comparison to similar ctgs.

Under .Crusher protocol - .357 = 45K, 9x19 = 35K .

Under Pizo protocol - .357 = 35K , 9x19, .38Super , etc =35K . Did every possable tolerence stack add up to moderating the .357 , while every possable variable combine to boost the 9mm ? Or was there implied or explicit gun industy influence ?

The gun industry is presently emphasiving .357 Mag in small frame and/ or lighter than air materials. Negative customer reaction to their shiney new guns being uncontrolable or painfull using major brand ammo would hurt sales. Meanwhile .357 Mag has been overshadowed by other cals for reputation of potent large game hunting, at least with mainstream factory loads. Those who do hunt with .357 , are likely to handloader , or purchase from smaller speciality ammo mfg.