You will most likely want to review this kind of issue with a competent trust/wills attorney.
We happen to have a trust, a will, and an estate. (Everybody has an estate, except maybe homeless folks.)
The trust is of the irrevocable type; it includes certain financial instruments and investments wherein specific tax benefits and other favorable terms are provided by federal law. It was written by an attorney; coulda bought some nice firearms for the fee. The trust is part of the overall estate.
The will provides for disposition of the estate, which includes additional property besides the trust, such as house, cars, household goods, bank accounts, a retirement account which I own and hope to use someday, and other stuff. Plus a few measly guns. The will was also written by an attorney; ditto on the firearms/fee alternative possibilities.
It's probably best to use an attorney for these documents instead of some online legal website, like LegalZoom, whatever. But the documents and legal advice are expensive. The attorney will tell you how much. (You could get out of Glocks, CZs, S&Ws and into STIs, Kimbers, etc. for the fee-equivalents.)
FWIW,