You can do it with a potato as long as you're willing to replace the potato after every shot.
*to be read in a Boston/cartoon-irish accent*
"Waste a potato like that? Do you want me dear old gram to rise from her grave and beat the tar out o' me with a switch?"
...Why yes, my knowledge of American Irish does come predominantly from The Departed and Boondock Saints, why do you ask?
More seriously, suppressors as a whole could well stand to be shifted off of the NFA entirely and transitioned into items which only require a BGC--especially if we could come to an agreement on instituting a system for those checks than can catch every transfer and apportion liability on those who don't take advantage of it and end up selling to a prohibited person.
Ditto for stocked pistols, honestly. Making a handgun less concealable is something that, statistically, means a lower chance for criminal usage.
Part of the problem with US gun laws is that portions of them run off legacy-laws from the Great Depression, other portions of them run off a 60s fearmongering push that was worried about inner-city blacks arming up, and another portion runs off a 80s/90s stew of some sensibility mixed with hysteria over cocaine-smugglers using legal machine-guns to gun down innocents...And the remainder run off of whatever the ATF presently thinks or, much more questionably (as with bumpstocks), what the President says should be the case--which is perhaps the most baseless basis for law possible.