I also ran a test with my pts g36 mags. The same frags he's using (out of the same box lol) would not feed in my mags. My controls were goldenball .28s, bioshot .28s, green devil .28s and green devils .3s, bastard double polish .25s All fed with no issue. The frags would get stuck, I had to bang and shake the mag upsidedown to even get them out of the mag.
I futz with V2s, V3s and V6s. I could be wrong... but probably, most likely not, as far as I know.