These "B-grade" Tachi mags work great! As long as you don't care about minor cosmetic blemishes these mags are fine. I scuff up my gear more than these flaws with normal use.
I like them a lot. Sometimes darts feed weird into my Stryker though, but I think that is a stryker issue more so than a magazine issue. I'm all ears to hear how to fix that feeding issue though. The darts kind of make a u shape, bending back towards the plunger tube.
I want to be absolutely clear. Nothing that Out of Darts darts supplies as a B grade item is B grade. Everything is A grade and amazing. It fits my Foam Knight beautifully and works flawlessly.
Awesome magazine lasts for days