The SP1 was the original civilian version of the Colt M16, the AR15, it was produced in regular versions w/20" barrel & the carbine (shown here) w/16" barrel. These rifles were semi only & did not use a military style pivot pin in the front receiver boss, rather they had larger diameter front upper/lower receiver bosses & used a double ended screw to secure the upper/lower together.
Album by willyp. Photos by willyp. 1 - 21 of 21 Total. 7971 Visits.