I'm looking to get some magazines for an AR 15. I'm new to this, I bought very little parts so far to build an AR 15. I do want to accumulate so magazines now. I've been to there website, and Cabellas site, called several gun stores. Now I'm confused even more. I don't know which ones to get. There are Gen 2 and 3 etc. With and without windows. I cant imagine what the diff. between different Gens could be. I spent a great deal of time to figure out the different Gens on Glocks. Can I please get some reponses on what mags to get and maybe a short version of the difference in some of them. I heard there are some issues with 30 rounders? Is that true? It seems 20 rounders are scarce or sold out. I did find some 20s without windows in gen 2, but I haven't a clue what Gen 2 is? Some of the part numbers suppliers have said they have are mosstly Mag 210 and then a few 211, 217, 243. Can I get some opinions or people to line me out a litttle. I dont mean to sound lazy, but I'm not a gun enthusiest, and its difficult for me to spend alot of my time studying this. But yet as expensive as these setups are, I want to make my purchases right the first time. Thanks.