For years, some of America’s most iconic gun-makers turned over sensitive personal information on customers — without their knowledge or consent — to the gun industry’s main lobbying group. Political operatives then employed those details to rally firearms owners to elect pro-gun politicians running for Congress and the White House.

The strategy remained a secret for more than two decades.

In a series of stories in recent months, ProPublica revealed the inner workings of the National Shooting Sports Foundation’s project, using a trove of gun industry documents and insider interviews.

We also showed how the NSSF teamed up with the controversial political consulting firm Cambridge Analytica to turbocharge its outreach to gun owners and others in the 2016 election.

Additional internal Cambridge reports obtained by ProPublica now detail the full scope and depth of the persuasion campaign’s sophistication and intrusiveness.

The political consultancy analyzed thousands of details about the lives of people in the NSSF’s enormous database. Were they shopaholics? Did they gamble? Did women buy plus-size or petite underwear?

The alchemy had three phases.

Phase One

Amassing the Data

How Cambridge converted those tiny bits of data into massive political wins has never before been made public. Its methods raise disturbing questions about how our personal data can be used to manipulate us.

“There is a natural desire to stay anonymous and keep your own information, and this is such a violation of that,” said Calli Schroeder, privacy specialist at the Electronic Privacy Information Center.

The NSSF has said its “activities are, and always have been, entirely legal and within the terms and conditions of any individual manufacturer, company, data broker, or other entity.” Larry Keane, senior vice president of the NSSF since 2000, said the trade group’s 2016 voter outreach campaign involved only commercially available data.

But Cambridge emails and a report on the NSSF campaign said the data included 20 years of information about gun buyers harvested from manufacturer warranty cards given to the NSSF. A contractor for the trade group also handed Cambridge a database of shoppers at Cabela’s, a popular sporting goods retailer. (The general counsel for Bass Pro, which bought Cabela’s in 2017, said the company had been unable to find evidence of Cabela’s “sharing customer information that was not compliant with their privacy policies at or prior to the time of acquisition.”)

Cambridge documents show the firm compared names and addresses in the NSSF and Cabela’s data against the same names and addresses found in a vast array of consumer purchase and lifestyle information, supplied by data broker companies.

Phase Two

Creating the Profiles

Next, analysts used an algorithm to profile and score each person’s behavioral traits based on the data and a psychological assessment tool called OCEAN that measures a human being’s openness to new and different experiences, conscientiousness, extraversion, agreeableness and neuroticism. From those scores, Cambridge organized people into five groups it called risk-takers, carers, go-getters, individualists and supporters. Members of each group received Facebook ads tailored to their group’s psychological profiles.

Below are political ads and descriptions of those personality groups pulled from Cambridge documents for the NSSF project. The ads include hypothetical messages along with the actual versions the firm sent for the NSSF’s election campaign, called GunVote.

Phase Three

Delivering the Ads

Cambridge found the targeted people on Facebook and delivered ads through the platform aimed at voters in North Carolina, Pennsylvania, Missouri, Ohio, New Hampshire and Wisconsin. Each pop-up ad said it came from the NSSF’s GunVote page, but they were crafted by Cambridge. The ads sent to potential voters in key states from June 21, 2016, through July 1, 2016, promoted Republican Sens. Richard Burr, Pat Toomey, Roy Blunt, Rob Portman, Kelly Ayotte and Ron Johnson.

Nearly 817,000 people saw the messages, according to Cambridge’s internal metric reports.

For the next three months, Cambridge included voters in Colorado, Florida, Nevada in the multistate blast of ads and videos on social media. Altogether, they garnered nearly 378 million views and drove 60,140,280 visitors to the NSSF’s website.

Cambridge also mapped out the locations of people in the five personality groups in the key states and gave NSSF contractors lists containing their names and addresses. The contractors examined the numbers and locations of each persona on a county-by-county basis. Then they mailed to the potential voters’ homes messages designed to persuade them to cast ballots for the gun industry’s preferred candidates.

See a detailed view of voters grouped by persona in each of the states targeted by Cambridge.