The Black Panthers incident that you're referring to:

https://en.wikipedia.org/wiki/Mulford_Act

The Mulford Act is a 1967 California statute which prohibits public carrying of loaded firearms without a permit.[2] Named after Republican assemblyman Don Mulford and signed into law by governor of California Ronald Reagan, the law was initially crafted with the goal of disarming members of the Black Panther Party, which was conducting armed patrols of Oakland neighborhoods in what would later be termed copwatching.[3][4] They garnered national attention after Black Panthers members, bearing arms, marched upon the California State Capitol to protest the bill.[5][6]

But also, going back prior to that:

https://en.wikipedia.org/wiki/Saturday_night_special

The earliest law prohibiting inexpensive handguns was enacted in Tennessee, in the form of the "Army and Navy Law", passed in 1879, shortly after the 14th amendment and Civil Rights Act of 1875; previous laws invalidated by the constitutional amendment had stated that black freedmen could not own or carry any manner of firearm. The Army and Navy Law prohibited the sale of "belt or pocket pistols, or revolvers, or any other kind of pistols, except army or navy pistols", which were prohibitively expensive for black freedmen and poor whites to purchase.[21] These were large pistols in .36 caliber ("navy") or .44 caliber ("army"), and were the military issue cap and ball black-powder revolvers used during the Civil War by both Union and Confederate ground troops. The effect of the law was to restrict handgun possession to the upper economic classes.[22]

The next major attempt to regulate inexpensive firearms was the Gun Control Act of 1968, which used the "sporting purposes" test and a points system to exclude many small, inexpensive handguns which had been imported from European makers such as Röhm, located in Germany.