Add or decrease powder for climate change.

[boomer135]

I moved from CA back to the east coast. I worked up a new long range rifle load today, and wondered what is the norm for changing from a dry climate to a humid climate when it comes to powder charges.

Did you need to increase or decrease? I am using a temperature stable powder (H-1000) but just curious of other folks findings.

['ol shooter]

I go with the published load recommendations. I know some powders are more sensitive to environment than others, but that's a matter of performance in a particular environment. Personally, I would never alter a load spec to attempt to compensate for environmental differences, I would compensate by re-zeroing the firearm for where you will use it.

[boomer135]

This is for precision shooting not hunting, so establishing a new zero won't cut it with the same load.

I had to adjust my loads when i moved to CA from the East coast, and I am now readjusting them due to the change of climate. The differences are small. Just curious of other folks changes.

As precision shooters we tend to be OCD on our loading data.

I go with the published load recommendations. I know some powders are more sensitive to environment than others, but that's a matter of performance in a particular environment. Personally, I would never alter a load spec to attempt to compensate for environmental differences, I would compensate by re-zeroing the firearm for where you will use it.

[Metal God]

Higher humidity means higher point of impact .

Im interested in some of the answers that may come up . I figure if it shoots little groups in San Diego it will shoot little groups in Colorado . If its not just a simple zero adjustment , my whole understanding of internal balistics is in question . I think that would hurt my feelings a little bit

Now if you're talking external balistics thats a whole different story . Yes if you have a long range load that shoots well at 5000 feet in altitude then Bring that load to sea level you very well may not be able to keep it supersonic to the same distance that you could at 5000 feet . So yes a charge weight would need to be adjusted to give you the extra velocity you need to shoot the same distance at sea level .