ok thats common with double stack midcaps..... I had that problem with my MAG brand midcaps too....
Problem is that when they mould the plastic, it has some imperfections, aka seam lines inside, so the guide plate thinggy gets sruck on those seam lines. and giving a gentle tap on the side of the mag, will usually clear/unjam it
I notice that these midcaps need a "break in'' period..... so basically, what you need to do now, is take your mags,BBs, a speedloader, open the tv, and start filling and emptying each mag several times until they stop jamming....
hope it helps
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