John Brown Gun Club is an anti-capitalist, revolutionary-activist organization that advocates for gun rights from a left-wing perspective and seeks to radicalize the rural working class. It provides armed security to left-wing protestors and trains other leftist groups in the use of firearms.
In 2019, an anarchist whom police claimed had previously associated with the Puget Sound chapter of the group attempted to carry out a terroristic act on an Immigration and Customs Enforcement (ICE) detention facility before he was fatally shot by police officers. 
The original John Brown Gun Club grew out of the Kansas Mutual Aid Collective in Lawrence, Kansas. One group, Redneck Revolt, came into existence after it split off from the gun club. On its website, Redneck Revolt explains that John Brown Gun Club consciously conceived of itself as an outreach group to the white working class to prevent them from becoming “foot soldiers of capitalism by adhering to a politics of white supremacy.” 
Mid-Missouri John Brown Gun Club
The Mid-Missouri John Brown Gun Club is one of the major chapters of the John Brown Gun Club. It identifies itself to be “anti-capitalist/-racist/-fascist/-patriarchy,” “pro-worker,” and “without a hierarchy,” instead claiming to “operate through direct democracy.” The group additionally states it “seek[s] the abolition of policing and prisons.” 
The chapter claims to operate a mobile soup kitchen and provide volunteer support at a local soup kitchen. Its members train at a gun range regularly and holds workshops to train its members in firearm use. It holds “brake light clinics” to “limit potential interacts with law enforcement,” it provides armed “security” to protestors, and provides “support, financial and otherwise” to “various efforts led by other groups, including a community bail fund” and a “nation-wide prison strike.” 
Steel City John Brown Gun Club
The Steel City John Brown Gun Club is a chapter operating in Pittsburgh, Pennsylvania. It is affiliated with the Pittsburgh Union of Regional Renters and PGH Mutual Aid and fundraises with them. 
Puget Sound John Brown Gun Club
The Puget Sound John Brown Gun Club is a chapter based in the Seattle and Tacoma areas of Washington state. The group has frequently been invited to demonstrations to serve as “security against rightwing aggression” by other left-wing protestors. In July 2019, members of the chapter defended a “Drag Story Time Hour” event occurring at a library near Renton, Washington, against right-of-center protestors who allegedly included members of the Proud Boys and the Three Percenters. That same month, the chapter provided “security” for the 2019 Trans Pride March in Seattle, an event organized by the Gender Justice League. 
Many of the Puget Sound John Brown Gun Club members participate in other left-wing groups in the region and actively seeks collaboration with “communities of color, indigenous communities, LGBTQ communities, all kinds of workers (from sex workers to tech workers), poor communities, houseless and migrant communities, religious minorities, those harmed by state violence (including prisons), and organizations whose stated goals align with our goals.” It has a contact form on its website for organizers to get in touch with them if they desire its “security” services for their events, or if they want “trainings” and lessons in “concealed pistol license assistance.” 
Puget Sound John Brown Gun Club joined with other left-wing organizations such as Labor Solidarity, Radical Women and the Freedom Socialist Party in counterprotesting a Patriot Prayer rally in Seattle. An individual that was handing out flyers for the group and who identified himself as Duke Aaron told the left-of-center Southern Poverty Law Center, “If the far-right is going to show up with weapons, we show up with weapons.” 
In July 2019, a former member of the Puget Sound chapter, 69-year-old Willem Van Spronsen, was shot and killed by police officers after he allegedly hurled Molotov cocktails at an Immigration and Customs Enforcement detention center in Tacoma, Washington. Van Spronsen reportedly had an AR-15 rifle with him, set fire to a building on the complex, placed flares strategically around the area including underneath a 500-gallon propane tank, ignited his own vehicle to explode and threw Molotov cocktails at various buildings. After pointing his rifle at four officers and refusing to drop his gun, the officers opened fire on Van Spronsen. The man committed the assault after a protest at the ICE facility earlier that day in response to the Trump administration announcing a round of deportations. Van Spronsen was a resident of Vashon Island, Washington, who claimed to be affiliated with Antifa and who had written and distributed a political manifesto prior to the attack. 
In 2020, Puget Sound John Brown Gun Club provided armed security and patrolled the streets of the Capitol Hill Autonomous Zone (CHAZ), a radical anarcho-communist takeover of six blocks of Seattle amid the wave of protests against police brutality following the murder of George Floyd.