So, are HP-38 and W231 really the same?

[ScottRiqui]

I'm almost out of W231, and I just got about 4-1/2 pounds of HP-38. I'll be using it for .380 ACP, 9mm, .38 Special, .40 S&W and .45 ACP. Whatever recipes I use, I'll be working them up fresh from starting loads, if for no other reason than the fact that it's a new batch of powder. I have two questions, though:

1) As I look through my load manuals, can I use recipes that call for either W231 or HP-38?

2) Would it be okay to dump my last four ounces or so of W231 into the HP-38 jug and mix it up well before I start working up the new loads? Or should I use up the last of the W231 separately?

 

[5R milspec]

If it helps I went from one to the other with out a hick-up

 

[g.willikers]

The load data from Hodgdon shows both powders with identical info.
So, they must be the same or close enough to be thought of as the same.
But mixing them is supposed to be a NO NO.
They might not be exactly identical.
Don't even mix different batches of the same powder.
There might be some variance, batch to batch.
That's why we're supposed to work up loads with any change of components.
Especially if the loads are anywhere near max.
Can't ever be too careful when messing with gunpowder.

 

[PawPaw]

From my understanding it is a consensus that HP38 and W231 are the same powder, simply repackaged. Likewise, H110 and 296. I don't know if Hodgdon will admit it, but that's what I understand.

 

[Jim Watson]

They are NOW the same stuff.
Since Hodgdon got the distributorship for Winchester branded powders, it has been convenient for them to just slap on whichever label, HP38 or Win 231, that they have orders for.

Ball powders are pretty consistent, I routinely back mix the last of an old lot with the new and have not seen a change in velocity.

 

[huntinaz]

But mixing them is supposed to be a NO NO.
They might not be exactly identical.
Don't even mix different batches of the same powder.
There might be some variance, batch to batch.
Can't ever be too careful when messing with gunpowder.

It doesn't matter if they aren't identical, mix it well and it will blend in and still be different from other lots... just like the lot he has now is different than what he's going to. Mixing together now and working up now is fine.

Ball powders are pretty consistent, I routinely back mix the last of an old lot with the new and have not seen a change in velocity.

Yeah. I don't shoot over a chronograph but have never noticed a change in accuracy or pressure signs going from lot to lot.

 

[Slamfire]

It is instructive to see in older reloading manuals the differences in maximum charge weights between HP38/W231 and H110/W296.

What that shows you is the lot to lot difference of identical powders.

 

[ScottRiqui]

Thanks for the replies, guys. But I have to say, I've never understood this part, even though I've heard it before:

Don't even mix different batches of the same powder.
There might be some variance, batch to batch.
Can't ever be too careful when messing with gunpowder.

If either batch of powder would be safe to use on its own, how could a thoroughly-blended mixture of the two batches be unsafe? Of course, I'd be working my loads up beginning from starting loads, but I do that anyway with any new batch of powder.

As an example, I have two 8-lb jugs of WC860. Rather than starting with one jug, working up an optimum load, and then having to do it all over again when I finish the first jug and open the second, why couldn't I just mix it all together from the start, work up a load, and then use that same load for the entire sixteen pounds?

EDIT - I just saw that several of you addressed my question before I was even done typing it. Thanks again!

 

[Jim Watson]

It is instructive to see in older reloading manuals the differences in maximum charge weights between HP38/W231 and H110/W296.

What that shows you is the lot to lot difference of identical powders.

In the older manuals, they were working with powder out of the same factory but through two separate distribution chains. So a tester could get lot to lot variations, maybe even in opposite directions for the two brand names.

Now, it is all handled out of the same warehouse, there is only one set of lot variation even though packed under two labels. Look at the Hodgdon www or book. The load data is identical, down to the last tenth of a grain and CUP. That tells me they only ran one set of tests and just wrote it down twice.
Same stuff. Hodgdon says so.

 

[g.willikers]

We really don't have any way to measure pressure.
While velocity and pressure are related, they aren't always directly relative to one another.
There's variables that can cause increases in pressure without an increase in velocity.
Maybe high pressures can be noticed, but maybe not.
Besides just getting an unexpected surprise, getting into the habit of mixing powders could result in mixing two different powders by mistake one day.
Oops.
My own experiences show that different batches of the same powder, bought at different times can, indeed, have different results.
No hugely, maybe, but definitely measurable.

 

[g.willikers]

When two batches of powder are mixed, how can you be sure that the mix is truly homogeneous.
What if the two batches are different and they don't mix entirely well?
What assurance is there that each and every cartridge will get exactly the same mix?
Just thinking out loud, here.

 

[Bart B.]

g.willikers, we do have a way to measure pressure. Buy the same systems SAAMI and some ammo companies use to test ammo. It'll cost a bundle of sawbucks, but it is doable. SAAMI would probably tell you whom to buy them from.

Here's a less expensive system, but it works best using the test methodology listed in SAAMI documents as far as test barrels and ammo handling procedures are concerned.

http://www.shootingsoftware.com/pressure.htm

 

[g.willikers]

That's amazing.
It's not cheap, at up to $800, but definitely in the realm of possibility.
Thanks for the link.

 

[SHR970]

g. willikers wrote: When two batches of powder are mixed, how can you be sure that the mix is truly homogeneous.
What if the two batches are different and they don't mix entirely well?
What assurance is there that each and every cartridge will get exactly the same mix?
Just thinking out loud, here.

What makes you think that same line of questioning doesn't apply to the powder that we buy from the distributors? Our canister grade powders are blended to keep them within a tighter tolerance of performance than the bulk powders sold to the .mil and the ammo manufacturers. Why do you think that some batches of a particular powder exhibit a wider ES and SD than other batches of the same powder?