Never heard of Mecgar making any S&W mags but if they did then why are so many issues with Shield mags collapsing the spring into itself?

Seems S&W has on at least 2X changed their springs to no avail!

Mecgar does make mags for some Keltecs and come with guns and are marked Mecgar!

I had to replace all 4 of my Shield mag spring with springs made by Wolff!