Lightweight bolt carrier for WE M4?
 

I know there was an aluminum lightweight bolt for the WETTI/closed bolt system.

Is there such thing as a lightweight carrier for the Open Bolt?

I love my M4 feel, but I play quite a lot in colder weather, and I would like to be able to field the M4 as much as I do the SCAR (damn rifle works at 0c on propane!)

I could always buy a second stock carrier and "lighten" it liberally, but if a ready-made one exists, that would be even better!