10MM Herco lead bullet load data ?

[tlen]

Got a large supply of Herco and I'm looking for load data for 155 and 180 LSWC bullets. I'd like to get 1100-1200 FPS out of a 5" barrel. Perhaps one of you still has an old 80s/90s Alliant/Hercules Reloader's Guide when 10mm was new and popular. Already talked with Alliant; they only have data for jacketed bullets and nothing using Herco since they are pushing newer powders.

 

[rcmodel]

1998 and 2002 Alliant guides list:
10mm - Herco
155 lead = not listed with Herco
180 lead = not listed with Herco

They listed it with a lot of jacketed bullet weights, but nothing for lead.

Lyman #45 does't list Herco with lead either.

rc

 

[NCsmitty]

I looked around a bit and could not find even one Herco load with cast bullets.
Here's a link to a test on the 10MM. It's got a few work ups with different powders.

www.sixguns.com/tests/tt10mm.htm


NCsmitty

 

[tlen]

Apparently there isn't much HERCO load data out there. There is sparse HERCO data for jacketed bullets in 10mm and .40 S&W.
Is there any rule of thumb for adjusting jacketed bullet data for lead bullets ? I'm not interested in max loads with lead bullets, just moderate target loads.

 

[rcmodel]

Herco is a very old shotgun powder slightly slower then Unique.

30-40 years ago, there was a lot more handgun data available for Herco as there were not a lot of good handgun powders to choose from then.
Since the .40 & 10mm are relatively new calibers, Herco had fallen by the wayside for handgun use by the time they came out.

I don't know of any reliable formula to convert jacketed data to lead data.
Burn rates vary somewhat by caliber and bullet weight, so any formula would be a WAG at best.

For instance, old Alliant data in the 357 Mag:
158 grain Lead SWC.
6.8 Unique gives 1,295 @ 33,900.
7.9 Herco gives 1,365 @ 33,900.

With a 200 grain Lead RN:
6.0 Unique gives 1,105 @ 33,900.
6.1 Herco gives 1,105 @ 33,900.

As you can see, with the heavy for caliber 200 grain bullet, Herco reacted quite differently, and reached peak pressure much sooner then with the lighter 158 grain bullet.

In all, substuting one powder or bullet types data for another is risky business at best, even when one is slower burning powder then the other.

rc