Strongly recommend a gun trust for essentially, everything.
My cliff notes, updates, and thoughts:
Make it irrevocable for a liability shield. Consider venue (South Dakota might be my strongest recommendation - they removed the law of perpetuities and protect against the release of beneficiaries). That doesn't mean you move to South Dakota, it's a formality mostly.
Then you name your initial beneficiaries and generically include all of their descendants, with a provision that they are not a recognized beneficiary until they have reached the legal age of possession of any and all trust assets then existing in their respective state of residence. Specify a C/O to maintain necessary documentation. Specify co-trustees to automatically be all effective beneficiaries with a threshold requirement to first pass a background check or complete any necessary background screening / licensing / application then existing at the time they reach the legal age of possession of any and all trust assets. Specify any trust assets that are outright illegal to possess in a given state of residence shall not be made accessible to a trustee then in-residence.
And then you have a son-of-a-bitch, that in theory, never dies, lasts forever, and never technically transfers firearms, so your great-great-great-great-great-great grand-daughter can stroll around with scary, antique weaponry that nobody else can legally possess.
Tons of errors and presumptions in this short description, tons of other things to consider including dissolution and things like Crummy and other provisions, but true trust/estate discussions would exhaust me and anyone reading my posts as well, I am interested in other high-level takes or known high-level defects if other people have done a lot of homework.