Light minenwerfer markings

[Collector56]

I recently acquired a nice minenwerfer round, it has the three black rings for HE, but there seems to be several other colours.
Looks like yellow at bottom, then black, then red, another black, then appears white and lastly another black (or am I imagining all this) any ideas on the meaning of these coloured rings?
Also has a tapered tin cover that should be fixed below the adaptor ring.

 

[JulienCD68]

Hello, This is a classic model.

The colors are probably due to wear.

There are models with a red stripe, but this one is clearly a black stripe model.