Culver's M1 Carbine Forum

[painter777]

Billy,
Where does the green color come from?
A long drawn out battle.
Thoughts of old cosmo turning parts green just doesn't fly. It doesn't explain why parts just opened from years in storage don't have the green tint.
M or Z type Phosphate finishes are a chemical reaction the end result being a rust preventative surface oxidized to clean raw steel. Still used today as a raw metal sealer for primer and paints to be applied over.

I believe the use of Zinc Chromate Green in a liquid form was used as the after park rinse.
This system was already in use by the DOD on aircraft.

Here's some more info about it,

Everything You Need To Know About Zinc Chromate

After reading this, you could see how playing with the tint would explain the numbers of colors we see on the carbines of today.

Just my thoughts,

Charlie-painter777