The problem with guns is not the guns themselves, but those who own them. Over the years many hundreds of thousands of people have owned guns for nearly their whole lifetime, completely blamelessly.
A small number, and it is a very small number, have misused them. Almost all of them have showed signs of mental instability or anger management problems
well beforehand
What needs to be tightened up considerably is the checks done on people before they get a gun licence and while they have it. For example, it should be noted on the medical records of every gun owner that they have a gun licence and it should be mandatory that the licencing authority be informed if there is any development in their health that could lead to misuse. I am not a medical expert, but I am sure medical experts could draw up a suitable list of problems calling for investigation.
Any gun licence holder reported for domestic abuse or for any criminal offence involving violence should immediately have their licence withdrawn, as they clearly have anger management issues.
I cannot see no problem with this, when DH developed sleep apnoea and had a microsleep when driving, he went straight to the doctor, who officially banned him from driving on the spot. Luckily I went to the appointment with him, I do not usually, so could drive home. If we can do this for sleep apnoea, we can surely do medically monitor gun owners.
Places like GCHQ regularly monitor all potential violent and terrorist sites. It should not be beyond the powers of electronics to link these with the gun registers, which should be held centrally, so anyone frequenting them or expressing violent or hate views, who holds a gun licence can be flagged up.