Home Forums Reloading Handgun Reloading HP-38 & W231 are the same, but...

Being bored during the stay-at-home order, I am reading reloading manuals for entertainment. I have always known HP-38 and W231 to be identical. Hodgdon's website has identical charges and pressure data for the two powders for 9mm 115gr bullets, but...Nosler's data is different for the two powders (see images below):





So what say you. Why is Nosler's data different for the two powders? Are the two powders no longer the same? Some other reason?

Different lots.

And that could also include primers, etc., but certainly the powder.

2/10 of a grain isn't very much. Lot to lot variation?

The more relevant question to ask is why the powder highlighted by a Gold Banner indicating it to be the best of the bunch no longer available...?

I’ve noticed that with .45 ACP data as well. No one could offer an explanation beyond lot variation. I think that it’s the same reason that different manuals have different data. It isn’t as exact of a science as we believe.

That was my thought...

Another thing to keep in mind while they've always been very close to the same powder they haven't always been the same powder. So depending upon how dated your manual could make a difference also

Exact science = oxymoron.

FWIW both sets of data come from the current websites of Hodgdon and Nosler. The images I posted are just screenshots.

Different lots of powder, different primer, different throat in the pistol, different case capacity, or difference in the hardness or bearing surfaces of the bullets. All could make a small difference. Nothing to be concerned over.

Look at the Nosler data--it gives different loads for the two powders--even though they are the same. That's the issue. Nosler states it used the same bullets, primers, and test gun.

This conversation is why I prefer to buy 8lb jugs of whatever flavor I load the most. Limits the lot to lot variation and the resulting retesting. Back during the 8 years of the dark lord I had to buy some mixed 1lb jugs of HP38 and 231. Later realized that one bottle of HP38 and one bottle of 231 had the same lot number. Don't know it that adds any answers to question or not?
I rarely load at max pressures so small variations aren't likely to hurt me other than maybe scores.

One obvious reason is the Hodgdon did not test canister samples of both powders. They only tested one powder since they know they are nominally identical.

Another reason - sample size. It is unlikely that both companies tested the same number if rounds - this could easily account for the small difference. Anyone who has done much experimentation with a chronograph knows that the average of a ten-shot string is not the same as the average of a five-shot string. Same thing for pressure measurements.

Then of course there are the actual differences in powder lot, primer, case, crimp, chamber and barrel dimensions......


.

HP38 on top
231 on bottom.
Hope this dispels the myth

OK, so same lot number for both types - sure looks like they were both filled from the same hopper at (or about) the same time!

I have the same thing with 44 mag. Win 296 and H110. For some reason I find Win 296 to be cheaper.

Both come from the same plant...same machine and have forever.

Back in the 1980s I was a commercial reloader. All I used was 231 or HP38 as it was the cheapest powder per grain of use on the market. It was also very clean and consistent and metered well.

Used to buy whatever was cheapest at the time I needed it...this was in 30 GALLON fiber drums. One time I ordered HP38 and when it was used up I pulled the Hodgens label off and under it was a W231 stencil on the drum.

Not sure but I believe at the time Olin was still making all the powder for Winchester. Winchester would just sell Hodgen the powder and they would put their label on it...

Bob

It would be interesting to go though some old manuals of theirs and see if they just re-published old data because they didn't retest each load. Could be one was shot a number of years ago. If they weren't out in the "reloading room" (my well house) I might be interested enough to look them up. But I'm in my getting ready for bed mode and it's raining too.

Another interesting thing I see is the +/- 100 fps increase using the W231 over the HP38. That's pretty substantial for a lot to lot difference with charge weights that small no? RJM, did you ever experience anything similar?

Hodgdon didn’t start listing HP38 in their books till manual 24 circa 88. 115 JHP was 4.8-5.2. Hodgdon 26 circa 92 lists
HP38 @4.7- 5.1 and 231 @ 4.7-5.2.
Nosler listed no pistol data until Nosler 3 circa 89 listed HP38 @ 4.7-5.2

Not much difference in data over what 32 years.

But nobody gives a sh*t. Give somebody proof that it ain’t changed or been retested in 30+ years and all goes fuc-king silent. Chirp Chirp the truth hurts. Big whumped dee doo made about 2 tenths.

Often, science is just an educated guess.

Hence the very technical term...."SWAG".