I collected a few land snail shells when I was in Ghana in 1997. But I doubt these were achatina snails—though perhaps they were. Performing a Google search, I found there are LOTS of varieties, and different colorations and types of striped patterns.

I'm showing two specimens of one subspecies, that, to my eye, comes the closest to the patterns I have seen on snail shell beads from West Africa. JDA.