Yo @sam_cw_leung One rebuttal I have is the cost of $250 for a bump stock. Here's an alternative:
https://hooktube.com/watch?v=_F618vo9Fos
Notorious for not being accurate. Also known to make the firearm hot as a #mofo.
Bump firing an AK or an AR is doable without the use of a "bump stock".
Bump or full auto, it's damned hard to stay on target. Recoil tends to lift the barrel.
It's another case of quantity over quality. I'll take shot placement any day.
Selective fire on 3 round bursts.
ymmv.