This weekend I was load testing and fired 50 rounds, 5 shots each, per .1 grain of powder.
I came up with an odd result. All rounds were loaded in the same sitting from the same batch of once fired fully prepped brass, that was also prepped in the same sitting. All shooting was done in the same sitting with no change in weather conditions. The chrono was never touched after initial setup and the gun was shot from a rest that never moved.
Varget Powder, Federal Brass, CCI BR2 Primers, SMK 168 seated exactly .010 off the lands.
44.0 Grains - Avg 2687 SD - 9.09
44.1 Grains - Avg 2703 SD - 8.17
44.2 Grains - Avg 2711 SD - 14.69
44.3 Grains - Avg 2736 SD - 10.00
44.4 Grains - Avg 2705 SD - 7.04
As you can see the standard deviations are very low. There were no oddball high or oddball low velocities in any of the 25 shots that made up the 5 averages above.
how in the hell did my velocity go from 2736 at 44.3 to 2705 at 44.4. The velocity dropped to the same average as 44.1 grains. My velocities consistantly climbed from 43.6 grains all the way to 44.3 grains and then suddenly dropped. 44.4 was the heaviest load I shot, so I don't know what would have happened at 44.5, unfortunately. That may have been a big teller that I didn't get.
Any ideas?
Thanks
43.6
I came up with an odd result. All rounds were loaded in the same sitting from the same batch of once fired fully prepped brass, that was also prepped in the same sitting. All shooting was done in the same sitting with no change in weather conditions. The chrono was never touched after initial setup and the gun was shot from a rest that never moved.
Varget Powder, Federal Brass, CCI BR2 Primers, SMK 168 seated exactly .010 off the lands.
44.0 Grains - Avg 2687 SD - 9.09
44.1 Grains - Avg 2703 SD - 8.17
44.2 Grains - Avg 2711 SD - 14.69
44.3 Grains - Avg 2736 SD - 10.00
44.4 Grains - Avg 2705 SD - 7.04
As you can see the standard deviations are very low. There were no oddball high or oddball low velocities in any of the 25 shots that made up the 5 averages above.
how in the hell did my velocity go from 2736 at 44.3 to 2705 at 44.4. The velocity dropped to the same average as 44.1 grains. My velocities consistantly climbed from 43.6 grains all the way to 44.3 grains and then suddenly dropped. 44.4 was the heaviest load I shot, so I don't know what would have happened at 44.5, unfortunately. That may have been a big teller that I didn't get.
Any ideas?
Thanks
43.6