would humidity cause powder to clump in the case

[n.c.outlaw2024]

or is it just inferior product sold for $$$$

 

[rwj]

Possible… but not likely

 

[rijndael]

Lab Answer: All powder contains a certain amount of moisture. When the powder is stored or during shipping, it can go through temperature cycles. During the cycling, the moisture can be pulled to the surface and cause clumping. Clumping can also be caused by static electricity if too dry or the powder has limited graphite content. You can break up the clumps before metering and they shouldn’t be a problem. This will not affect the powder performance, so your product is fine. Accurate 1680 labels are designed in Pink. As a side note, specification for testing powder is at 70° F and 60% humidity.

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[Doom]

Some lots of powder contain more acetone, a solvent used in the manufacturing process than cause clumping. I had a pound of IMR Target that was still literally wet with acetone and clump in large balls. It was almost like static but it wasn't. Likely to be a problem when container is first opened. The acetone will dissipate fairly rapidly afterwards.

 

[CJ6]

If it's clumping in the case, I'd say it's do more to compression.

 

[BoydAllen]

This is my theory about one way clumping can happen. Powder has some moisture content. When it is loaded into a case there is water vapor in the spaces between the granules. If the loaded round it cooled below the dew point for that level of water vapor water will condense on the inside of the case and that can cause powder to clump. While I generally do not take my loaded ammo apart, one time when I did the powder was clumped and appeared to be slightly moist. It was not that way when I loaded the rounds. Everything looked normal. The loaded rounds had not been rained on or immersed in water, so I concluded what must have happened. Like I said, this is just my theory. In recent years I either load in conditioned space, with relatively low humidity, or at the range, and fired soon after loading. There have been times, on a cold foggy morning, when loading at the range that I noticed that the brass was damp, probably from condensation.