Trump was in line with the NRA’s policy on bump stocks. That’s why he supported it.
Fact check false
NRA-ILA Files Friend of the Court Brief Urging the Sixth Circuit to Vacate ATF’s Bump Stock Rule
“ ATF had determined that bump stocks were not machineguns on ten separate occasions from 2008 to 2017. But that changed in 2018, when ATF announced that it would review its regulatory definition of machinegun. NRA-ILA filed comments opposing ATF’s reinterpretation at that time. Nevertheless, ATF reversed course and classified bump stocks as machineguns. That change prompted several lawsuits.