I just traded for two LEO marked Sigma magazines in .40 S&W. When I took them apart for cleaning I noticed that one of the magazine springs has some type of red or maroon coating (like a powder coat). All of the other Sigma magazines I have for both 9mm and .40 S&W have a blue coating. Does anyone know what the significance of the red vs the blue coating is? Is one stock power and the other extra power? Were the SV40F magazine springs different color? Any ideas? Because they are LEO only marked they are probably from the mid 1990's when the high capacity magazine ban was in effect. The wierd thing is both are LEO marked but one is blue and one is red.

Another observation is that the red spring tapers earlier (much like a single stack magazine) compared to the blue springs.