in your will ? upon your death, they transfer to him ( assuming he can legally posses them) TAX FREE on a form 5. If you worry about paperwork, fill the forms out ahead of time and place them with your will. Much simpler, less legal scrutiny from BATF and courts, and really easy to accomplish. Make sure you and your wife have a will anyway. the trust thing was a way to get around the CLEO sign off on the old form 4. This is no longer an issue. A number of online trusts are being challenged by BATF incurring additional legal costs. It really complicates matters for executor who do not understand the "trust" concept. I am dealing with one of those right now, Guy paid $1600 to move his NFA over to his "gun trust" and lawyer is now having issues with the trustees. Also dealing with a "no will " gun collection. Executor is selling ALL the guns for market money, and those relatives who were "promised" a particular gun are SOL.
Contact your lawyer, state laws vary. Probate rules vary.