having used a truck gun for a number of years in a number of formats i will share what my experiance has been.
1. Semiautos when fired out the window can have dissapointing results to the inside of the glass. maybe magnified by steel cases. .22lr while not dinging the glass much do go in the defrost vents on the dash.
2. being a proud kanadian and following all the laws strictly (shooting out the window of a motor vehicle not withstanding) a loaded detachable magazine is a real winner when a responce is required quickly to mr. wyley's mocking you from a safe 50m away.
3. open sights are more forgiving to your side veiw mirror. please dont ask.
4. of the actions left, i found i personally could cycle a bolt faster and more comfortably while resting my forstock on the half raised window.(or half lowered depending on which camp you ascribe to)
5. you stopped to enjoy the moment of snuffing out some creature that was just minding its own buisness, dont waist it by losing the moment of impact in the recoil of somthing too high powered.
Other than that i got nothing for you =)
Jody