Ok Understand I'm anal and I never thought that this info would be useful to anyone but....I Have 2 RRA rifles and 54 30round USGI mags...Pretty much have all the makers covered,Colt,cooper,parsons,FN,labelle,okay,Sanchez, etc,etc,etc....And took the time to sit down and chart all the mags by maker and if they drop free or not...Anyway here are my findings:....All my colt and parsons mags drop free,most of my labelle,Sanchez and fn mags drop free(about a 80% drop free rate).Some of the Okay and Center ind mags drop free(about a 50% rate) and about a 30% rate on the Sanchez and coopers......Now keep in mind that I'm talking about MY lowers and MY mags so YMMV..If I ave a choice I usually look for parsons because colts are more money....Hope this helps...........UNDERDOG