[bbbean]

I keep a can of compressed air on my reloading bench for blowing small amounts of loose powder, cleaning media, and spent/stuck primers around. Great tool, and makes it pretty easy to keep the press clean as I work.

However, I recently changed setups to load 9mm, and noticed that I was dumping powder all over the press and getting a huge weight range on the first several rounds. It took me a while to realize that after I got it set up, I'd gone over everything with the compressed air, and had accidentally sprayed too close to the powder funnel, leaving enough moisture for it to collect powder and clump.

A quick disassembly and thorough cleaning with a paper towel got me back up and running with consistent powder drops.

[ihatepickles]

Using compressed air near the powder measure can also impart a static charge to the plastic. That can throw off the charge weight too.