HS-7

[Nannyhammer]

Looking to see if anyone has any pet loads using HS-7 with 185 and 190grain cast bullets in the 10mm.  After digging through several manuals and only finding jacketed bullet loads I'm looking for a starting point.  I've also checked with Hodgdon and they provided the little bit of info that they had.  A search for the Winchester equivalent didn't turn up much data either. I have acquired 16lbs of this powder and wanting to start burning it up.  Appreciate any help you can provide. 

[Taterhead]

Ken Waters Pet Loads lists the following:

170 gr Hornady JHP 10.5 gr @ 1151 fps. Remarks are "near max"

180 Sierra JHP 10.0 gr @ 1102. states as "near max" and "accurate"

200 gr Hornady FMJ 9.0 gr at 954 fps. Remarks were normal pressure indications and accurate.

Ken Waters did not develop loads with the benefit of pressure testing equipment, but relied on measurements of case expansion as proxy. Colt Delta Elite was his firearm.

[Taterhead]

 Here is data from my Speer #12. I verified that it is identical to #13 and the 155 gr and 180 gr data in #14. #14 dropped 200 gr data altogether.

[The_Shadow]

I had always wonder how HS-7 would work out, but it wasn't around for me to buy.  Its always cool to test the old powders and study results.
Back in late 1989 early 1990 I developed my own loads with Blue Dot because I was using it in 38/357 and 44 spl / mag and 12 ga.  My loads turned out to be the same as the Speer supplement they sent me between Speer 11 and 12 manuals.  My cast 175 grain bullets loved the 10.4 grain load of Blue Dot and were very accurate even out to 130 yards from the S&W 1006.

[Taterhead]

Cast data is scarce. Knowing that Speer data tends to run hot, I might start a grain below their start load for cast and work up or down from there, depending on what you want to do.

[Nannyhammer]

Thanks for the info......that helps me get me started. Mainly wanting these loads for practice but will stick with longshot for my hunting loads.

[sqlbullet]

I use jacketed bullet data for the same weight and nose profile bullet, reduce 10% and work up.  Expect to reach velocity/pressure with less powder using cast bullets, so a chronograph is very useful here.

A word about the increased pressure.

This seems counter-intuitive to anyone that has ever driven a cast bullet through a barrel or has had to drive a stuck copper bullet.  Lead bullet engrage easier, and have lower friction through the barrel.  How do we end up with higher pressure then?

Properly fit cast bullets seal the bore better than jacketed bullets.  They are generally at least .001" larger in diameter.  If correctly manufactured the bullet hardness is aligned with the expected pressure levels and the bullet will obturate in the elastic range to better seal the bore. (copper is far to hard to do this.)

Since cast bullets seal the bore better, less pressurized gas escapes and pressure and velocity go up using less powder.

[The_Shadow]

Burn rate chart 2010 shows Hodgdon HS-7 was slower burning than HS-6, Winchester AutoComp, Ramshot Silhouette, VihtaVuori 3N37, VihtaVuori N350, Hodgdon HS-7
Then these were slower than HS-7, VihtaVuori 3N38, Alliant Blue Dot,  Accurate Arms No. 7, Alliant Pro Reach, Hodgdon LONGSHOT 

HS-7 was said to be the same as Winchester 571 powder

[The_Shadow]

Winchester data from 1999  HS-6 is the same powder as Winchester® 540, and HS-7 is the same powder as Winchester 571.

[Nannyhammer]

All, thanks again for the assist!