The Store 63 is a Vietnam Era 5.56×45 weapon system built in a variety  of variants: rifle, carbine, automatic rifle (top-fed), light machine gun, medium machine gun, fixed machine gun  and last but not least a commando version (100 round drum fed). In the LMG flavor you had a cyclic rate of about 1000 rounds per minute. The carbine variant was built with a 1:12 and 1:9 twist.