In contrast to all of you, I welcome slippery slopes. Then I don't have to put my faith in politicians holding the line and remaining steadfast. Plus, I find guns scary, so I think the modifier is appropriate for any firearm.
I think "assault slingshot" has a nice, ominous ring to it.
Link: https://www.rrstar.com/story/news/crime/2020/09/14/rockford-man-accused-of-killing-brother-with-slingshot/114391060/