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Department of Justice

U.S. Attorney's Office
Middle District of Florida
Roger B. Handberg, United States Attorney
For Immediate Release
Friday, April 21, 2023

Federal Jury Convicts Two Men for Conspiring To Transfer Unregistered Machinegun Conversion Devices Disguised as “Pen Holders”

Jacksonville, Florida – United States Attorney Roger B. Handberg announces that a federal jury today found Kristopher Justinboyer Ervin (43, Orange Park) and Matthew Raymond Hoover (39, Wisconsin) guilty of conspiring to transfer unregistered machinegun conversion devices that they referred to as “Auto Key Cards.” Additionally, Ervin was convicted of seven counts of transferring unregistered machinegun conversion devices, three counts of possessing unregistered machinegun conversion devices, and one count of structuring cash transactions to avoid currency transaction reporting requirements. Hoover was also convicted of four counts of transferring unregistered machinegun conversion devices. Ervin faces a maximum penalty of 110 years in federal prison and Hoover faces a maximum penalty of 45 years in federal prison. The sentencing hearing is scheduled for July 31, 2023. Ervin was first charged on March 2, 2021, and Hoover on January 26, 2022. Both Ervin and Hoover have been remanded to the custody of the U.S. Marshals Service.

According to testimony and evidence presented at trial, in January 2021, Ervin’s bank contacted the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) to report that employees believed that Ervin was trafficking in machinegun conversion devices. Subsequent investigation revealed that Ervin was running an online business selling machinegun conversion devices, known as lightning links, etched into metal cards, which he referred to as Auto Key Cards. Ervin described the Auto Key Card as a “pen holder,” a “novelty,” and a “political sculpture.” A lightning link can be dropped into an otherwise legal AR-15 type firearm and convert it into a fully automatic machinegun.

In February 2021, federal agents from ATF and the U.S. Postal Inspection Service (USPIS) surveilled Ervin and observed him dropping off dozens of packages at an Orange Park, Florida post office, each of which was determined to contain unregistered machinegun conversion devices.

The ATF examined the Auto Key Cards and a firearms enforcement officer was able to remove the pieces of a lightning link from an Auto Key Card using a common Dremel rotary tool in about 40 minutes. When the firearms enforcement officer placed the two pieces of the lightning link into an AR-15 type firearm, it converted the semi-automatic firearm to be fully automatic.

Hoover operated a YouTube channel called CRS Firearms on which he advertised Auto Key Cards. In his videos, Hoover stated that “laws only work if we follow them” and encouraged his viewers to use “discreet ordering” by mail to purchase Auto Key Cards. Hoover stated that his viewers could cut a lightning link out of the Auto Key Card, “drop it in your receiver, scratch your full auto itch, throw it away when you’re done” and “no one’s the wiser.”

Hoover’s videos advertising the Auto Key Card led to a substantial increase in Ervin’s sales. Ervin sold more than 2,000 Auto Key Cards in only a few months. Multiple purchasers of the Auto Key Card testified at trial that they had learned about it from Hoover’s videos and purchased the Auto Key Card intending to use it to convert their AR-15 type weapons into machineguns. Ervin compensated Hoover for his advertisements by sending cash through the mail and, on one occasion, a Louis Vuitton purse.

In March 2021, federal agents executed a search warrant at Ervin’s home and recovered Auto Key Cards containing etchings for more than 1,500 lightning links.

This case was investigated by the Bureau of Alcohol, Tobacco, Firearms and Explosives, the U.S. Postal Inspection Service, and the Internal Revenue Service – Criminal Investigation. It is being prosecuted by Assistant United States Attorneys Laura Cofer Taylor and David B. Mesrobian.

This case is part of Project Safe Neighborhoods (PSN), a program bringing together all levels of law enforcement and the communities they serve to reduce violent crime and gun violence, and to make our neighborhoods safer for everyone. On May 26, 2021, the Department launched a violent crime reduction strategy strengthening PSN based on these core principles: fostering trust and legitimacy in our communities, supporting community-based organizations that help prevent violence from occurring in the first place, setting focused and strategic enforcement priorities, and measuring the results.

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