Then the definition of "machine gun" would have to be edited from what it currently is.
Here's how AWR Hawkins put it today:
http://www.breitbart.com/big-government/2018/03/10/trumps-doj-moves-ban-manufacture-possession-bump-stocks/On March 10 Sessions announced the DOJ was close to securing the ban. The DOJ is accomplishing this by redefining the term “machinegun” so that the term covers machineguns and non-machineguns as well. This allows the DOJ to treat firearm accessories that are not conversion devices in a manner consistent with conversion devices.
In other words, although bump stocks do not convert semiautomatics into automatics, redefining the term “machinegun” allows bump stocks to be regulated (banned).
[It's really sad, and scary, that this is the third occasion in about a month that Lewis Carroll has provided the same apt quote: ‘When I use a word,’ Humpty Dumpty said, in a rather scornful tone, ‘it means just what I choose it to mean, neither more nor less.’]
Also go ahead and try enforcing and confiscating property from the People.
Especially sticks and PVC pipe and rubber bands and pants belt loops. Oh, and hands and arms. This is gonna be good. Fucking "multiburst trigger activator" morons.

Excellent article on this "words have meaning" aspect in this very context at The Zelman Partisans:
http://zelmanpartisans.com/?p=4960‘SPLAININ’Words. Effing. Matter.
Gun owners want to know what you plan to ban next, so we can plan accordingly ourselves. Are you going to ban semiautomatic rifles based on the original AR-15 pattern, or are you going to ban double-single action 1911s, bullet-piercing bullets, ghost bullets, heat-seeking bullets, 30 caliber rapid-fire magazines, shoulder things that go up, and multi-burst trigger activators? None of which exist, but all of which have been proposed for bans.

M1A2 Abrams Main Battle Tank