If powder is dryer, will this cause increased velocity?

[ShtrRdy]

I've been working with a 6mm Creedmoor lately. I came up with a sweet load using H4350 and the 105 gr Hybrid. I switched to a different powder lot, made a slight adjustment to charge weight, and was back with the sweet load. Recently I loaded up some cartridges and the velocity is about 25 fps higher. All the components are the same; brass, bullets, primers, powder, OAL.

The only thing I can think of is the powder might be a little dryer. My thinking on this is if the powder is dryer, its density is lighter. Then when I measure a charge weight I'm actually gathering a little more powder to get to the same weight. With a little more powder comes a little more pressure. Does this sound reasonable?

 

[Sheldon N]

The only thing I can think of is the powder might be a little dryer. My thinking on this is if the powder is dryer, its density is lighter. Then when I measure a charge weight I'm actually gathering a little more powder to get to the same weight. With a little more powder comes a little more pressure. Does this sound reasonable?

Yep, same weight but less water = more active combustible material (powder).

 

[spife7980]

http://bulletin.accurateshooter.com/2018/03/humidity-and-powder-burn-rates-what-you-need-to-know/

 

[ShtrRdy]

Thanks for the link Spife. Since I live in a dryer part of the country should I just spread the powder out and let it dry out a bit then put it back in the container? That way maybe the powder will be more consistent when I pour some into a hopper to be dispensed.

 

[spife7980]

If you’re keeping the lid tight when not pouring out powder and storing it inside of a conditioned space I think you’re better off keeping it sealed as possible.

Someone was in her with this same experiment awhile ago drying it out in an oven. I can’t advocate for that but he seemed pleased with the results.