If the ATF adopts whatever EO he puts out we're kinda screwed, they are not exactly an agency you want any negative interactions with. Here's an interesting article I just found on Trumps EO on bumpstocks.
Looks like the Supreme Court refused to hear the case, but was later overturned by a Federal Court
https://www.atf.gov/rules-and-regulations/bump-stocks
On December 18, 2018, Acting Attorney General Matthew Whitaker announced that the Department of Justice has amended the regulations of the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), clarifying that
bump stocks fall within the definition of "machinegun" under federal law, as such devices allow a shooter of a semiautomatic firearm to initiate a continuous firing cycle with a single pull of the trigger.
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Supreme Court leaves Trump bump stock ban in place

By
Ariane de Vogue, CNN Supreme Court Reporter
Updated 12:29 PM ET, Mon March 2, 2020
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Trump's Bump Stock Ban Just Lost Big in Federal Court
“It is not the role of the executive—particularly the unelected administrative state—to dictate” the terms of criminal law, said the 6th Circuit.
“It is not the role of the executive—particularly the unelected administrative state—to dictate” the terms of criminal law, said the 6th Circuit.
reason.com