They are indeed like magic... I use unmodified Uzi mags in a few of my guns, and the LULA saves your thumbs like nothing else. If you ever get into pistols, the UpLULA is also pretty amazing on some guns with very heavy mag springs.My biggest complaint about my 9mm carbine is loading a 32 round colt mag by hand. Boy was that painful and slow. I went online and found this at brownells:
WOW!!!! It is increadible. Works like magic.
What ammo are you using for your testing?