National Ordnance made carbines from 1960 till about the mid 70's. The early ones used mostly USGI surplus parts while they made their own receivers and barrels. Four separate blocks were made serial number wise over the years. It seems that National Ordnance used demilled receivers for many of their production. Others was made overseas and were considered to be soft. There is no way to tell what carbine was made with what type of receiver. They also made carbines under the name Alpine, Rowan-Becker and Santa Fe. They made an estimated 50,000 carbines. Universal carbines are also considered to be in four different groups. The early ones were made with USGI parts. Later they had to make all of their own as the more they had to make the quality seems to have dropped. Their last ones made are considered to be a step above junk compared to their originals.