Is HS-7 the same as WW-571?

Question

A ammo reloading question.

Need old ammo data of powder that they stoped making years ago; WW-571

I went to their site;

http://www.hodgdon.com/smokeless/shotpist.php

There at Hodgdon they say they are “identical”. This make me a bit concerned because the pressures ARE a bit different.

But with their libility situation I doubt they would make that claim if it were not true.
I’m confused here, any opnion?

Answer 1

They may well be the same, as Hogdgon do not actually make powder, they buy from manufacturers and package. One chart that I have shows the powders to be the same , another shows a slight difference.According to "Guns Magazine" they are one and the same, see;
http://findarticles.com/p/articles/mi_m0BQY/is_10_50/ai_n6180926
I find it unlikely that any magazine would make this statement if it were not 100% correct, for numerous reasons.
If you are still in doubt, either;
Try a load of 571 10% lower than the maximum for HS-7 and chronograph it, or preferably, to be on the safe side, post on this site which cartridge that you require the load for, I , and I am sure many others, have data for 571.

Edit; No two books will give the same loads or pressures, even different years of books from the same manufacturer. I must agree that it is confusing for all.
It is a safe bet that they are one and the same, as;
1/ Hogdgon do not make any powders themselves.
2/ WW are the only company making spherical powders and as both are spherical powder, both must be made by WW.
3/ The Hogdgon site, as you say, maintains that they are the same.
Tell me what cartridge that you are loading for, and I will find the data for you.

Answer 2

No, they are not the same.

In the powder burn rate chart in my one of my older Speer Manuals, HS-7 is listed as being a little slower burning than Olin/Winchester 571.

The burn rate of HS-7 is between Al-8 and the old Hercules 2400. Since Alliant has taken over Hercules and reformulates most of the powders, I don't know if that is still true.

Doc

Answer 3

I have looked in every book I have, and even though they are used for the same purpose(heavy field loads and magnum pistol) none say they are the same.
One website had one person saying they are the same, but another person said they are not. I would be careful using data for one powder and using another powder.