Oh dear. I read with interest these discussions of mortar attacks and grenade blasts and such, and am so happy it doesn't happen at my shooting range. Shovelsful of dirt on your action? Thousands of rounds without cleaning?
Where I go to shoot, it is peaceful, well run, with a range officer, and people smiling. You shoot a few rounds, maybe even a hundred or so before you call it a day.
Go home to a cold beer or other beverage of your choice, and meticulously clean your rifle.
I guess from a purely academic perspective these inquiries are relevant to ME, but it sure seems far fetched as viewed from my comfortable leather easy chair.