When it comes to gas mags, I've fixed plenty of GBB WE pistol mags. Turns out two aren't actually leaking; TM doesn't use a silent fill valve, so it seems like the mags are venting, but they aren't. But two ARE leaking, and I've tried rotating the o-rings 90 degrees, soaking them in warm water, and many coats of silicon grease. Overnight, I removed the two o-rings and put them over the back of a screwdriver to try to reform them to circle; I'll see how that does in a bit.