The trust willmaker will generate for you is going to be a valid trust - that doesn't make it particularly suitable for use as an NFA container.

Examples: Most vanilla trusts specify that trust assets are to be sold to settle the grantor's debts. You probably don't want that happening with your NFA goodies.

Most vanilla trusts contain boilerplate clauses about careful stewardship of trust assets, which is kind of at odds with you regularly using and thus devaluing the SBRs and suppressors- maybe causing a baffle strike or having a KB.

There are a bunch of other things which may be particular to different boilerplate trusts, or peculiar to each state's trust laws which may not be suitable for your uses. Those trusts will be valid, legal entities which can own NFA, but encumber your usage of the items if things ever got unhappy between you and other trustees.

Using a lawyer will let you look for pitfalls like that which you would like to do differently for a trust whose assets you're intending to use and share with other trustees, etc. If you don't give a damn, or are just cheap, then use willmaker or a boilerplate handed out by some gunstores.