When I bought my Mini, Ruger didn't sell Hi- cap magazines, but my Mini functioned perfectly with 20 Rnd. no name mags. However, I've never fired anything but brass cased 55 Gr. ammo. This includes Reman ammo and cheapo imported ammo as well as quality name brand ammo. BTW I lube my mini the same way I lube my Garand and I've never had an FTF or FTE. I hope you get the kinks worked out as I feel the Mini is one of the more enjoyable weapons out there. I hope you end up enjoying your Mini as much as I do mine.