I use green devils I have tried the .20 and .25 so far, not any .30's
This is due to the fact my local store only carries green devils
I have had some double feed issues, but I believe double feed is a magazine problem at least for myself. I had Zero problems with either of my hi cap mags, double feed occurred only when using a mid cap Kings Arm plastic mag(120)
I will someday order some bastards and try them out.