Honestly, I can't say. Maybe you got lemons, or I got really good ones. Having only used WE mags in my two pistols, I can only report how they work for me, which is good. Only one of my four P226 mags leaked badly (it was internally damaged, as I had messed with it before I knew what I was doing), and none of my G17 mags have ever had any issues, nor have had any work done to them. My TM MP7 mags were all sorts of messed up when I got them, but soaking in warm water, silicon grease, and 144a maintenance gas fixed all four of those up. Generally, I get a full mag of bbs from them all, except for sometimes the 50 rnd mag I have for my G17; but I have a mini-can of gas I carry in a spare M4 pouch just in case.