Is the AI and AICS mags the same? I am looking at building a REM 700 SA in 223 and looking at the AICS stock and the Mcree stock. The Mcree takes the AI mag but unable the verify if they are the same. Why a 223 bolt? My local range is only 500yds, less recoil and a lot less expensive to practice with. Did I mention it was cheaper! I believe the XLR chassis has its own mags. Thanks for the help.