Powder manufacturer's load data a function of liability ?

[Virginian]

I have loading data published by Dupont, Winchester, Hodgdon, and Hercules going back to the late 1970's. I even have an empty can from some of the first Blue Dot, with load data on the back, that I have saved. I don't load many shotshells anymore, but I do still load rifle and handgun. The one thing that is almost universally consistent across the board, is that the maximum, and many recommended, loads have decreased over time. Back in the '80 to '88 time frame, things were changing rapidly. I find the earlier loadings tend to produce velocities a lot closer to what's listed, too.
Now, were the powder formulations changing, or were the data changed to decrease the potential liabilities? My opinion is the powder stayed the same. I know I loaded Blue Dot to the max loadings I got off that old can until steel shot finally put an end to my quest for the 100 yard duck load. And I never saw a sign of excessive pressure. Nor did I see any signs when I kept pushing 117gr. BTSPs thru my 25-06 with 53 grains of 4350, even after Dupont was no longer on the label. And, I am still pushing 170 gr. JHPs out of my 357s with 13.0 gr. of 2400 (and yes that load is in a 1980 Hercules powder manual). It is a stout load, but has performed well out of at least seven different 357s now.
I think the powder companies have just played it safer as liability lawsuit awards have skyrocketed. I can't blame them for that. I have called all of them at one point or another and asked them if their formulations have changed. And they said no. And then I said I was using old data. And then they said, oh well the component performance could vary. And then I said "Oh, so you don't check burn rates of the finished product?" And at that point they would kinda say yes and get real wishy washy.
I am real careful when I do load any maximum loads. I use a very good powder measure, not the one on my Dillon progressive, and check frequently. And I always work up with a new gun or brass, etc. I wear stout safety glasses, and I have seen a Remington 760 in 30-06 blow up from an accidental double charge, so I know it pays to be diligent.
I figure if they ever did speed up the burn rate on a powder, that would be dangerous. I have never seen a warning label on powder "Do not use except with such-and-such load data".
What's your opinion? Do you only use the latest current loads, or do you do like I do?

 

[mscott]

I agree with you on the current published data. I typically work loads up that are over max for rifles and most IPSC shooters are loading well over max listed for open guns. All of this needs to be approached cautiously and with knowledge of what is going on. Penalties for mistakes can be severe. I'd like to have a few manuals from the 70's for just such a comparasin.

 

[brickeyee]

There have been improvements in actually measuring the pressures developed.
The old coper crusher system had a significant amount of inertia present that limited the sensitivity to the actual peak pressure present.
Piezo sensors are much more accurate (and sensitive), and at least some loads have likely been reduced when the more accurate data became available.
Many of the powders appear to have slowly wandered over the years as factories changed.
I have used the 'same' powder from lots many years apart in identical loads and gotten VERY different velocities.

And yes, liability would increase if a manufacturer stuck with old data when newer data indicates the data should be changed.

 

[Virginian]

brickeyee posted - "I have used the 'same' powder from lots many years apart in identical loads and gotten VERY different velocities."
Excellent point. I check velocities and that is my "flag", but I have never run across it. I should also add that I load only a very few loads in the maximum range since I quit shotshells.