Number of times the government has ever "come for your guns": Zero.
It has never happened.
It has never even been mentioned.
What has been talked about a LOT are a universal background check - where EVERYBODY, even private sales, have to have a background check.
AND
Titling guns.
In the end, what most rational people want is for guns to be treated like cars. You buy one, you get a background check and a title for the gun in your name. You sell that gun, you and the buyer make a quick trip to the gun store, pay the 10 dollar fee (or whatever it is) and he gets a background check and the title of the gun transfers to him.
Here's why the NRA fights both of those:
Most guns get into the hands of criminal by way of legal buyers. They buy the guns for 400 bucks and sell them privately to criminals for double that. Criminals will pay it because the only other way they can get one is to steal one, and they sort of need the gun to do their stealing.
That would cut gun sales by an estimated 40%. It would devastate the gun industry by making it nearly impossible to sell a gun to someone that shouldn't have one.
So the gun nuts that deal illegally are against it and the NRA is against it because the gun manufacturers are against it.
Would it end all gun crimes?
No. Of course not. But within 20 years it would reduce it by an estimated 70% as the guns available dry up and the only people left owning them are, surprise surprise, the people that can legally own them.