This is a subject that really needs to be given serious thought. I grew up in a house full of guns. My Dad and his Dad were collectors, although Grampa's was quite small. When my Grampa died in 1980 my Gramma gave them to my Dad and I. On birthdays and Christmas she would give us a card that read "take a gun". We each got half.
My Dad was a collector of old Single -Shot rifles, and he had some really valuable ones. He also had some newer stuff. He passed almost 18 years ago. My Mom is still alive, and they all belong to her, although several are in my possession. If she needs money, I will help her sell them. In her will, I get the guns. She knows I know about their value, so no problem there.
My advice is get a list of TRUSTED collectors to help your heirs. I remember my Dad joking with one of his friends that they should call another guy they knew who is nationally known as a dealer of fine older Single-shots and tell him my Dad had died. They laughed and said he'd probably be on Mom's doorstep, cash in hand the next day. Truth is, when Dad died, mom got a very nice sympathy card from him, with no mention of buying anything. I spoke to him on the phone some time after that, he never asked if anything was for sale.
I started making a list of my guns, with descriptions and values. Missus P&R Fan will have a list of people I trust to help her dispose of my stuff. One of them I met through this Forum. I trust all of them, and know she will get full value.
It just takes a little planning.
Jim