04 March 2008, 08:34
kududeSubstitution of WW760 for H414 in 9.3x74R
Today I tried 760 in lieu of H414. I started with 66.3, and increased to 66.5gr and 66.7 grains. Generally, the velocities were lower with 760.
The average velocity for the 66.3 load was: 2272
The average velocity for the 66.5 load was: 2242
The average velocity for the 66.7 load was: 2247
The higher velocities for the 66.3 was probably attributable to a clean, lubed bore.
The data for 760 is more in line with the info provided on the Hodgdon Web site.
I will try steps of 2gr from 66.7 from 66.9 to 67.5 and see of we get a second "node" when the bullets come together. If not, it look like 66.5 is the load. Kudude
PS: The first set of rounds was used to "zero" the scope, which was used for set #4.
04 March 2008, 21:23
DuaneBWhat you are seeing is the difference in lot numbers. H414 is W760. The data is completely interchangeable using normal "work up" procedures to make sure lot number variations don't get you into trouble. FWIW DuaneB
05 March 2008, 09:07
kududeDuane,
I treated the shift as a "Lot change" and backed off about a grain and a half. I found it interesting that the old 760 was more in line with the Hodgdon site data than my newer H414 powder. Kudude