223 cal. & is early model w/out forward assist. currently set up w/22LR conversion bolt & has original pencil thin bbl, add on flash hider & Oxford sighting system. Comes w/triangular hand guard & is in good used condition, includes a std. 223 cal. bolt & total of 5 22 cal. magazines. The 22 cal. conversion is a Military Armament Corp w/original box, this package also includes an original Colt 3x rifle scope w/box plus 7 early Armalite & Universal marked aluminum magazines. Overall a very nice SP1 w/accessories.