Can PC powder go bad???

[762X51]

I figured the only thing in powder paint is polyester resin and pigment so what exactly can go bad, right? Well for the last year or so I've been chugging right along using a Kawasaki green powder and enjoying much success and shiny happy bullets. Suddenly my bullets went from shiny and glossy to extremely rough and flat. I tried to eliminate any variables so I got a new shake-n-bake container, fresh powder from the airtight container it is sealed in and new airsoft BBs, and still the poor finish. I can't for the life of me figure out what might have happened to cause this. Any input would be appreciated. For what it's worth the old container of Harbor Freight red still works just perfectly. So much for higher end powder.

[OS OK]

Bill Clinton might have a different opinion of that Harbor Freight 'working perfectly'..."depends on your definition of perfect!"

[bangerjim]

Moisture is your big enemy. Lumps, clumps, sticky, poor flow and coating. If you live in humid swampy areas, you really need to seal VERY well!!!!

Here in the desert SW, it is not a problem for me.

[Daveco]

I've got some assorted powders that are at least 15 years old and that haven't been treated very well as far as storage is concerned. I drug out a bottle last week that has a screw on lid, and the powder inside the bottle tied up in a plastic bag with a zip tie holding it closed, and it still works beautifully. I'll try to post a picture....

Got them sized earlier today and hope to get a few loaded up either today or tomorrow. They are cast from a Lee .452-200-SWC mold.
Daveco.

[Dark Horse]

Moisture in the container and storage in too warm conditions can mess with your powders usability. Both cause clumping, and generally interfere with its ability to take on a charge.