Theory I have but can't prove is that a huge number of accidental gun deaths and suicides are murders that the cops are just too lazy to investigate https://people.com/human-interest/dog-shoots-kills-owner-freak-hunting-accident-kansas/
@mtsw people can be dumb with guns, but “put a loaded rifle in the cab with the safety off” strikes me as improbable. If nothing else, rifles are big and unwieldy. Having one point *at* the driver seems just implausible.
Most of the hunters I know would either use a case (good hunting rifles aren’t cheap), or would lay it horizontally, where a negligent discharge would strike the door.
Quick, someone check if he owed a cop money or something.