This is no longer true. Part of 41F was to clear up that individually owned NFA items can be passed to your heirs, tax free, on a Form 5. You need to state who gets the property in the event of your death, and it's helpful to fill out a sample Form 5 so they won't have to figure it all out.WITHOUT a trust, on your passing, there would be a complex transfer process, involving the ATF, the forms, and the $200 tax stamps per item.
If you want NFA toys, buy them. Right now the wait times are ridiculous, unless you're doing an eForm 1 (building it).
ATF has allowed the executor—or other person authorized under State law to dispose of property in an estate—to convey firearms registered to the decedent without being treated as a voluntary transfer under the NFA. ATF has also allowed such transfers to be made on a tax-exempt basis when an ATF Form 5 is submitted and approved in accordance with 27 CFR 479.90. When the transfer of the firearm is to persons who are not lawful heirs, however, the executor is required to file an ATF Form 4 and to pay any transfer tax in accordance with 27 CFR 479.84.