7WSM and H1000

[jcann]

I've shot Berger 180gr hunting VLD's using 65.8grs H1000 and have constantly achieved +/-2,950fps. The other day I decided to try my hand at shooting 180gr Hybrids using the same load of H1000. Base to ogive was the same for both loads, same die bushing, and same primers. The only difference being I annealed my brass prior to loading the Hybrids and had to use a different lot of H1000 (I had used up all the different lot of powder). When I ran the Hybrids through the chronograph I was getting 90fps less velocity; 2,860, 2,864, 2,867, 2,857fps.

Could this velocity difference be due to the annealing, different length of bullet bearing surface, and different lot of powder or do you think the main culprit is the different powder lot?

 

[AKGuide]

I would think that it is a combination of both annealing and the different lot of powder. Annealing makes the necks all uniform tension, but also releases the bullet easier allowing less initial start up pressures. Add that the new lot that you have may be on the slower side and I believe this is the reason you have lost velocity. I would load a couple at .4 grains over and .8 grains over to see what happens velocity wise. My guess is that with a touch more powder your velocity will come back to where it was. The ES and SD look good though.

Reuben

 

[brentc]

I've shot Berger 180gr hunting VLD's using 65.8grs H1000 and have constantly achieved +/-2,950fps. The other day I decided to try my hand at shooting 180gr Hybrids using the same load of H1000. Base to ogive was the same for both loads, same die bushing, and same primers. The only difference being I annealed my brass prior to loading the Hybrids and had to use a different lot of H1000 (I had used up all the different lot of powder). When I ran the Hybrids through the chronograph I was getting 90fps less velocity; 2,860, 2,864, 2,867, 2,857fps.

Could this velocity difference be due to the annealing, different length of bullet bearing surface, and different lot of powder or do you think the main culprit is the different powder lot?

Shorter bearing surface causing less pressure is the most likely culprit along with a different powder lot. Pump your powder charge up a bit to get the velocity where it was with the VLDs.