Have you spoken with an estate planning attorney who is thoroughly familiar with the current estate planning laws of your state? This is a special practice area, plus the laws are continuously changing/being revised.
We now live in Georgia. We met with our attorney two years ago after moving here from Austin, TX. He provided my wife and me with a "Personal Property Memorandum" (available on request via a PM) which allows us to each specify those personal (firearms included) items which we own that are to bypass our estates and go to specific people. Otherwise, our personal items (firearms, jewelry, watches, collectibles, etc) all become a part of the entire estate itself, which if not requested by an heir will be converted to cash and distributed according to the provisions of our separate wills. This also removes the valuables from the grasp of the creditors and all other claimants.
Just as has been previously mentioned, I also maintain detailed records and documents in a large binder for all of my firearms, including my historical letters from Smith & Wesson. The detailed records are also in an Excel spreadsheet on my computer hard drive.
I have already spoken with 3-5 trusted collectors in my city, explained to them the situation, and obtained a commitment from them to assist my "personal representatives" with the disposal of all of the firearms in my collection. The cover page in my binders provides the names, addresses, contact numbers, my relationship with them etc.
Our oldest son is our "personal representative". During recent visits I have explained to him where all of the firearms are located, the contents of the binder, and where to find the additional detailed information on my computer hard drive.
Probably all of us are "dynamic collectors" in that the specific items in our collection are continuously changing. My challenge is to ensure that my records are always up to date. That in itself is another story!