Anyone else have this problem...

My 30rd mags (the ones that were made by welding 2 20's) don't work in any of my SAR8's (Greek, steel).  The mag catch just doesn't sufficiently engage the cutout in the mag.  They work fine in my real HK, but not in the clone.  All 20's (steel, aluminum, or thermelt) work fine though.

Any know fix for this?  I'm reluctant to mess with the mags for fear they won't work in the HK.