In article in the Wall Street Journal on Tuesday, May 14, 2019 about federal licenses held by firearm collectors, they had this discussion:
The curio and relic license that Mr. Saenz possessed is issued by the federal government for antique firearm collectors. It streamlines the purchases of historic or novel guns and would have allowed Mr. Saenz to avoid California regulations including a 10-day waiting period and a minimum 30-day span between purchases of handguns, according to the law-enforcement officials.
There are currently 52,000 such licenses that are active in the U.S., according to the Bureau of Alcohol, Tobacco, Firearms and Explosives. By contrast, 17.2 million Americans had concealed carry permits in 2018, according to the Crime Prevention Research Center. . . .