You cant compare a RRA AR15 to a RRA AR308 that takes odd ball magazines. Save yourself the headache and get one that takes standard P mags, like the one i suggested. Hell, even the DPMS LR308 takes p mags. The Armalites built after 2011 take p mags as well. The older AR10 Armalites are great rifles, but use proprietary magazines. But at least they work very well.