I just inherited an Armalite AR-180 that was made in England. It has less than two magazines through it. It has the factory 20mm scope and comes with ten Sterling 30 round mags. I looked on YouTube and saw a video on how to break down and clean it, (Easier than an AK-47) Does anyone on this forum have any experiences with this rifle, and is there any thing I should know before I go out Saturday and shoot it. It says 5.56 mm on the side of the receiver, but some mags are loaded with .223 and some others are filled with 5.56 x 45. Any help would be appreciated.