I know that no one wants to hear this, but I will say it again. If you have to use your gun on the street, there is a very high probability that you will be confronted by police officers and ordered to "drop the gun, now!" If you hesitate because the street is concrete and the gun is expensive, I can almost guarantee you will no longer have to be concerned about damage to your gun or anything else in this world.
If the gun is not damaged before that, it will be taken from you when (not if) you are arrested. You will be thrown in a cell and the gun will be tagged and tossed on the concrete floor of the evidence room.
(And please skip the business about how you are a good guy and the police will just let you walk away from a shooting. Even if the case is clear cut self defense, the street cops won't make that decision; it is very unlikely that you are going to gun down someone on the street and not be arrested.)
First, having been in law enforcement and taken two armed subjects at gunpoint, I never ordered them to "drop the gun". It was "put the gun down, NOW!" and I preferred they set it down as gently as possible. I had no idea at the time whether or not the gun would fire if dropped, and didn't want to take the chance.
Secondly, when we did take control of the weapon(s), they were handled carefully, first to prevent accidental discharge, second to preserve any evidence that might be on them. We also had a very meticulous evidence handling procedure, because we understood that, in some cases the evidence would be returned to the subject, and the policy was to return it in as close to original condition as we got it...(yeah, we were relatively progressive for the '80s...)
Third, while I never had to disarm anyone after a shooting, other officers on my department did, and in an obvious, clear-cut case of lawful self defense, the subject was not necessarily arrested; transported to the P.D. to be interviewed, maybe, but on more than one occasion they were allowed to leave, pending disposition. And if it was ruled justifiable, the weapons were returned to the owners.
Arbitrarily saying that "you WILL be arrested" or "your weapon WILL BE mistreated/damaged" is a blanket fallacy. It may be true in some (if not most) jurisdictions, but it's not a certainty.