Magazine dust cover?

[Stumpkiller]

Has anyone seen or know of a cap, sleeve or dust cover to fit a M11 (or Axis Short) magazine for pocket carry?

I'd like to keep a spare in my vest pocket when hunting and a plastic or rubber cover to keep out crud would be a nice addition.

[mudpig]

when it's nasty out, I just put an extra mag in a ziplock baggie in my pocket