You want irreversible damage, try a kid or an adult shot
accidentally. Guns may be somewhat less lethal than automobiles, but that doesn't stop the State Governments from insisting that drivers be licensed, and that cars be licensed too. I've been away too long, but in many countries, proof of insurance is mandatory when getting a license for a car. I think there should be mandatory insurance for fire arms too. That way the insurance companies can cover the cost of the damage done by all those Licensed, and Responsible Gun Owners who kill themselves or others either intentionally (suicide or murder) or accidentally.
And every gun owner may be "Law Abiding" right up until something makes him snap and shoot a family member, or members or himself or someone else. Dangerous weapons should be treated as dangerous all the time (in other words, not taken for a trip to the local mall or supermarket), Whether loaded or not. That used to be part of the NRA's education package for young people. Always treat a gun as loaded until you've opened it and proved it's not, Don't carry a loaded gun across rough terrain, unload first and reload when you get to where you will be shooting or hunting. Did the United States get stupider since the 1950's?
If you fly model Airplanes you join the Academy of Model Aeronautics, the AMA, an umbrella group for people who fly model aircraft in the US. When you join you have to pony up for insurance, because of *all the lethal accidents caused by Model Airplanes!* (damned few per year). Why not guns, for Heaven's sake.