Method Used to Arrive at Publish Load Data?

[rdtompki]

I've seen relevant load data for WSF poweder and 147gr lead ranging from Lyman (3.4gr - XXX @1.058" OAL) to Hodgdon (3.7 - 4.1gr @ 1.169" OAL). As it happens I've loaded at both OAL at the low end and had good results?

When a powder manufacturer tests a new powder, or in the case of WSF when Winchester many years ago tested WSF, do the test over a broad range of OAL/powder weight combinations mindful of chamber pressure? Or are they really just looking for one range at an OAL that "works" and use as a starting point results from a similar powder? 1.169" is on one end of the SAAMI spec and 1.058" seems pretty short. Of course bullet characteristics will enter into the results.

 

[joneb]

As a example you will see the same two powders tested at different times with very different charges, different powder lot? different testing equipment?
I seen W-231 and HP-38 data differ but it has always been the same power, this is why we read the reloading manuals so we can discern the pressure signs and safety work up our loads.
When cross checking data, look for COL, primer, case and trim length and the bullet used.

 

[ljnowell]

As a example you will see the same two powders tested at different times with very different charges, different powder lot? different testing equipment?
I seen W-231 and HP-38 data differ but it has always been the same power, this is why we read the reloading manuals so we can discern the pressure signs and safety work up our loads.
When cross checking data, look for COL, primer, case and trim length and the bullet used.

I don't believe they have always been the same. Since 2006 they have been absolutely identical. For some time before that they were both produced at St Marks in Florida but the hp38 didn't have the identical burn rate characteristics.

 

[hanno]

I don't believe they have always been the same. Since 2006 they have been absolutely identical.

According to an email I got from Winchester they have always been the same. FWIW

HP-38 and Winchester 231 are exactly the same powder. They always have been the same powder. The only difference is the label on the bottle. Because they are the same powder, the data would interchange.

Mike Daly
Customer Service Manager
Hodgdon Family of Fine Propellants
Hodgdon Smokeless Powder
IMR Powder Company
Winchester Smokeless Propellants
GOEX Blackpowder

 

[rdtompki]

My sense is that when testing the manufacturer(s) just look for one range/OAL that works versus a more expansive test. Nothing wrong with doing so, but makes sense in light of published loads for similar bullets that appear quite different. Of course start low and work up or, as is my situation shooting steel, find the softest load that cycles reliably since PF is not an issue.

I was just surprised that 3.3gr WSF @1.08" worked just as well as 3.7gr WSF @1.15"; may have even cycled the gun better. I'm going to try 3.2gr, but the 3.3gr recoil is very nice.

 

[Wil Terry]

ALL factory ammuniion and factory loading data is obtained using SAAMI pressure specifications;ie; MIN-MAX, Nothing else.
It is NEVER the same EXACT results as every carridge fired is a new CASE, a new PRIMER, a new PROJECTILE ETC ETC ETC...and the prssure gun BBL heats up....it has very VERY minute wear from every single cartridge fired. AND the hewmaditty is different every day etc etc etc...
And so it goes...

 

[buck460XVR]

Published data shows us just how many variables there are when it comes to hand-loading ammunition. Two powders that are identical(W231/HP38, and H110/W296 for example) or even the same powder tested by the same lab, can come up with very different values when testing is done on different days. The data from Nosler using their 158gr JHP in .357 is a good example. We all know H110 and W296 are the same powder, just distributed under different names. But Nosler shows a max of 14.8 of W296 under the 158 pill giving a velocity of 1540 fps. They then give a max of 15.9 of H110 giving a velocity of only 1490 fps. Which one is correct? Why both of them. Different days, with different ambient temps and humidity perhaps, maybe just different lots of the same powder. This is why most experienced handloaders do not solely rely on one source of data and will compare data from several sources before developing a new load. This is also why most manuals include a safety factor in their max loads as a margin of error. While one can assume from the Nosler data that even a charge of 15.9 of W296 is as safe as that same load with H110, we also need to realize that their 15.9 load under their 158 pill is starting to push the envelope. I've found that the middle of those maxs are the most accurate for me in my .357s. I don't pay as much attention to a published manuals max load as I do to the loads they claim are the most accurate.

 

[mdi]

I believe the testing is done with the listed OAL for the particular bullet listed. As we know the OAL is dependent on the bullet design and that info/dimension is prolly supplied by the bullet manufacturers...