Anyone who ever accidentally fires their loaded gun should lose their firearm privileges. And that includes cops, such as the one who recently accidentally fired his gun while using it as a fucking flashlight at the Columbia protest.
I think that's a pretty "common sense" measure that both sides of the second amendment debate should be able to mostly agree on. There may need to be more nuance for it to be in line with the second amendment constitutionally, such as it being a privilege lost only for a number of years and which can be restored after taking a gun safety class, or some such. But it sure would be a start.