Stolen shamelessly from Sharp as a Marble, this comment by DustyDog:
If gun confiscation happens, it won’t be a shoot out. You’ll get 3 letters of advance notice filled with dire threats. Then a final warning (which will arrive a week late), and two late notices, full of threats. You’ll hear that the people running the database can’t keep track of how many weapons were turned it, so if you turn in anything and get a clean card, you’ll in the record as having no guns. So you drive to the location to find out it was misprinted on the form. You call and google, and find the right place. You’ll go through a humiliating pat-down for knives and drugs, but they won’t take the gun or ammo you have in your hands – that’s somebody else’s job; wait in line. You’ll wait in line all day long, to be turned away.
You’ll come back earlier tomorrow, wait all day, and turn in a gun.
When you turn in your gun, you get a receipt with no unique code. They throw your gun in a completely unsecure box, in an unsecure room. “It’s easier now. When the door was locked, the guns would pile up until there was no more room. Now, the boxes are always empty in the morning.”
The next week, you get a letter saying that due to a database crash, the government is not sure if you turned in your guns. You’ll be ordered to fill out a form, under threat of imprisonment. You’ll have the option of affirming that all your guns were turned in, or that they were not.
If you affirm, you’ll get the same letter every six months. If you refuse to affirm, you’ll go on a waiting list. Two to five years later, a guy with a high school diploma will show up to take your guns. You won’t need a gun to kill this guy, a ten-year old could beat this guy down. He won’t have your name right and the names of guns on his list won’t be the names of guns ever actually made; the records are obviously all mixed up. If you tell him your name is Juan and you’re renting from [you], he won’t be back for another 2 to 5 years.
That’s pretty much how Canada’s attempt at long-gun registration went, before they finally gave up.