I know H110 is temp sensitive … or at least that seems to be the consensus, but this seems a bit much for a 23 degree drop in temp … from 72 to 55 degrees. These are 5 round groups with .5 grains of H110 increase between each group. Started at 18.0 and ended at 20.5
Using 300 grain, gas checked, pan lubed cast bullets out of a Lee C430-310-RF Mold. WLP primers, H110.
Velocity difference between Day 1 at 72 degrees and Day 2 at 55 degrees:
Group 1 (18.0 gr): -78.3
Group 2 (18.5 gr): -93.5
Group 3 (19.0 gr): -136.6
Group 4 (19.5 gr): -156.7
Group 5 (20.0 gr): -146.8
Group 6 (20.5 gr): -149.8
This wouldn't be caused by a 23 degree temp drop would it?
It's possible my scale wasn't calibrated correctly, but for that to be the culprit, I would think the velocity drop would be uniform across all groups. The groups seem to progressively worsen, the stabilize.
Would love to hear your thoughts!
Using 300 grain, gas checked, pan lubed cast bullets out of a Lee C430-310-RF Mold. WLP primers, H110.
Velocity difference between Day 1 at 72 degrees and Day 2 at 55 degrees:
Group 1 (18.0 gr): -78.3
Group 2 (18.5 gr): -93.5
Group 3 (19.0 gr): -136.6
Group 4 (19.5 gr): -156.7
Group 5 (20.0 gr): -146.8
Group 6 (20.5 gr): -149.8
This wouldn't be caused by a 23 degree temp drop would it?
It's possible my scale wasn't calibrated correctly, but for that to be the culprit, I would think the velocity drop would be uniform across all groups. The groups seem to progressively worsen, the stabilize.
Would love to hear your thoughts!