??? The steel portion of the mag seems the same not sure what you meant.are you positive the steel is different?
I'm surprised the SW mags would have different followers than the Walther ones. The darn things are so critical that they are at the third design right now I think. You'd think MecGar would only manufacture the latest/greatest rev. But hey, I could be wrong about that of course. I have two 10rd Walther mags with SW floorplates. I suppose they're hybrids??? The steel portion of the mag seems the same not sure what you meant.
Perhaps the polishing is a tad nicer, hence a richer bluing, but for mags it doesn't really matter.
As far as why I like the Walther mags more, I just think that the followers are a nicer design and work smoother in the Walther mags compared to my SW99 mags.
$20+ better perhaps not, but in my case I bought them for $25each shipped so it was a no brainer for me to go with the Walther mags. YMMV.
Be warned that I've yet to see anyone post about a reliable promag magazine in their p99....I've seen a ton of unhappy comments though.These aren't made by Walther but they have lots of sizes.