Approximately when did the US change to razor wire?

Barbed tape was first manufactured by Germany during World War I, as an expedient measure during a shortage of wire. Since it was simply punched out of a rolled ribbon of steel tape, it could also be manufactured much faster. This early barbed tape had triangular barbs, and no reinforcing wire. Consequently, although it was harder to cut with ordinary wire cutters, it was easier to cut with shears, and generally weaker.

Commencing in the early 1970s, unreinforced barbed tape started to be commonly used in perimeter barriers in US prisons. Several manufacturers of barbed wire and barbed tape began to offer barbed tape with a reinforcing wire in the early 1980s. The first to be manufactured was probably around 1981, although this has been subject to a patent dispute. Early brand names of reinforced barbed tape included "Man Barrier" and "Razor Ribbon"; the latter probably lent its name to the modern slang term.

The whole story can be found
here. Interesting stuff believe it or not.....

Patrick

We were getting issued both when I was in Germany in the late 70's. The Razor wire was what we got the most in 79 - 80.

Dave