Lyman 50 Manual, Minor discrepancy 45 ACP W231 and HP-38 same Bullet

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Master Blaster

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Today I received my hardcover copy of the Lyman 50 manual. :):)

Of course I had to look at the .45 acp loads right away as that is my favorite caliber. No surprise that the two best powders for the round have been unchanged for many years W231 and Bullseye.

For the last few years 231 has been difficult to find so about a year ago I bought a few pounds of HP-38 which is exactly the same powder under the Hodgden label as W231.

SO imagine my surprise when I looked at page 2 of the .45 acp loads and found 231 and HP-38 both listed for a jacketed bullet load with different charge weights and different max loads for the same bullet. The data in the manual shows that there is a significant difference in pressure and velocity between the two powders for the same bullet case and primer!

SO I go to the front of the book and look up pistol powder burn rates and there on page 67 it says " HP-38 and W231 are Interchangeable" in the load data!

Yet in the only .45 acp load listed for HP-38 it shows a big difference between it and W231. As I never load to max for .45 acp this is not really a practical concern. Also I recognize pressure can vary between firearms, and I may not use the same case bullet and primer as listed in the manual.

Interesting and a bit puzzling. So I can only conclude that there is a difference between lots of the same powder. As the saying goes start 10% below max and work up.
 
I spent some time in the ordnance business and lots of time in the chemical manufacturing business. To assume different samples of solids taken from the same vessel are identicle is not reasonable. There are all sorts of reasons to stay away from max loads. The fact that things like smokeless powder and corn flakes settle is one reason. Also the best methods we have of measuring chamber pressure aren't all that good.
 
Lot to lot variation is 5 to 10%, depends on mfg. I think Hodgdon recently claimed they had tightened theirs down to 5. This is one reason to buy 8lb jugs if developing a near max load.
 
IF Lyman actually used their own pressure measuring equipment then the factor of lot to lot is there. Also if they used the data provided from Hodgdon and from Winchester those tests were probably not the same setup at the same time either. Why would they retest the round/charge when The data was available for years and what we reloaders already use. Remember years ago the two companies were in competition to sell their branded propellants and Winchester cost 10% more around these parts then. Just my two cents.;)
 
It has nothing at all to do with lot variations.

It's just that Lyman didn't retest every load in every caliber all over again for every book that comes out.

For instance:
.45 ACP 185 JHP

Lyman #47 --- Published 1992
HP-38 = 5.8 MAX
W-231 = 6.1 MAX


Lyman #49 --- Published 2008
HP-38 = 5.8 MAX
W-231 = 6.1 MAX

Would not surprise me at all if that's what #50 says too.

It's old data from before when the two powders really were two different powders.

rc
 
They don't update their data, but they claim that you need new manuals to keep up to date... Lyman's may be good, and I know you should verify from multiple sources, but this just adds to the confusion, and potential danger.
 
This is why we are careful reloaders start low and work up our loads, no matter which powder we use. No company who puts out a manual can retest every single load. New powders and new cartridges get new data, the others are reprinted.
 
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I agree that we must take responsibility to use caution in working towards max loads, but, like ArchAngelCD said, and rcmodel alluded to, if a powder changes composition, to where it is the same as another powder, the publisher kinda owes it to the customers that are paying for the data to retest. Which still doesn't excuse us from verifying data from multiple sources, working up, being careful, and paying attention.
 
I believe that Lyman will stop pushing a cartridge combination when the accuracy starts to degrade even before reaching max pressures so perhaps that's at play here? They don't actually pressure test many different cartridges and 45 ACP is likely one of them seeing as it runs at such low pressures and the resulting velocity using powders in the acceptable burn rates is well enough to keep things in the pressure range where they belong.
 
It would take about 25 years for the few guys doing the testing at Lyman to test every bullet, powder, and caliber. By that time some of the data would be old. The newest data is listed in PSI not CUP.
 
They could also be intentionally publishing "old" data so that long-held stocks that aren't identical to the modern formulations are safe. For example, look at all the caveats that swirl around the .45-70 government cartridge for the same reason.
 
Thanks I believe you folks are correct as the same exact load and data appears in the 49th edition. The only difference is that in 50th they have a C after the data to let us know its "cup", which probably means its old data, as testing is now done in PSI.
 
Makes perfect sense to me that only portions of the data get updated. I'm sure they want to keep up with new calibers and components, which doesn't leave a lot of time to verify and test old data. They still have to take the time to go through all the data to make sure something didn't get screwed up somewhere along the way. Not to mention that it gets expensive to be buying new components all the time that you don't make anything on (i.e. they are providing a valuable service above and beyond their own interests).

A careful method of experiment is going to require multiple tests of the same setup and recipe. How do you determine max and min? On the high side, you have to run far enough over to make sure the data shows linear results far enough to ensure no MAX load suddenly pressure spikes if you go a couple tenths over. On the other side, you don't want to see erratic results that could result in a squib load. That all takes time, and I'm sure those guys have other jobs to do besides spending every day going through the same recipes that haven't changed in years.

Actually, I would not be surprised if they did test a lot of the loads to make sure nothing has changed. Just a quick check to show the data is in the same ballpark. No point in working up new data if there's no need to.
 
When I saw W231/HP-38 discrepancies in published load data, I suspected old load data being reused from when W231 was different powder from HP-38.

Now that we know W231 and HP-38 are the same exact powder, what I realized was if different bullet type/profile, OAL/COL, powder charges, etc. were used, resulting difference in bullet seating depth/neck tension would produce different max chamber pressures and muzzle velocities.

But if both powders are listed under the same bullet type/OAL/powder charge but showed different max pressures/velocities, I would have to say that it's old load data being reused without new testing.

BTW, for those who have the new Lyman #50, does 40S&W page still show .401" groove diameter for test barrel instead of .400"?
 
BTW, for those who have the new Lyman #50, does 40S&W page still show .401" groove diameter for test barrel instead of .400"?
Click to expand...

Yes it does, page 422
 
- Sigh - Oh well ...

I was hoping they would use .400" 40S&W test barrel for Lyman #50.

So, if you are reloading 40S&W, slug your barrel and if the groove diameter is .401", use Lyman load data.

If your barrel's groove diameter is more typical .400", use more conservative load data from powder manufacturers or conduct your powder work up carefully (I would consider dropping my max charges).
 
I have never heard or seen a method of calibrateing a high pressure surge that has a repeatable primary standard. The piezo and strain gauge methods give good looking curves that show what we think they look like. However, they prove nothing.
 
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