9mm vs 38 super single stack mags

[EARLYTB]

What is the difference between a 38 super magazine and a 9mm magazine ie are the followers interchangeable?

 

[nognog]

I am not sure about single stack mags, but I know for double stack mags like SV & STI the 38 Super mags and 9mm are basically the same. To use a 38 super mag to load 9mm rounds, a 9mm spacer will be needed.
The followers for 38 Super and 40 SW can be interchangeable, but those follower can not be use with 9mm. The 38 super follower will be too long for the 9 mm round magazine.

 

[Canuck223]

The single stack 9mm 1911 mags have a spacer filling in the back (or front) of the mag, so no, the followers are not interchangeable.