anything about all the calibers possible with an AR???...obviously .223,.308 (and it's metric brother ), 5.56 ,.204 but i've also heard about .22 fireball/hornets??? .22 rimfires???....but what are ALL the options out there as of today????
maybe a link to some of the newer options???
*edit* just saw one for the .17 hm2 as well
