Hi all, I'm new here. I think I've caught the AR-15 bug - I want one . I've briefly read some posts on building my own as opposed to buying a complete gun. I live on Long island, NY. I don't know what too look for as far a brands go, like RRA , Bushmaster DPMS....ect.is one better than the other - I like a 16" barrel, the 6 position telescoping stock . this is mostly going to be a gun for the range. In NY there is a 10rnd cap on mags. But , my friend bought a new RRA here in NY from a gun shop, with a couple of 'Pre-ban" 30 rnd mags, and it is legal. If this is the case, what is the purpose of buying a complete 'Preban' rifle? If I decide to build my AR-15, would I be able to buy 'pre ban' 30 rnd mags and still be legal?