Sometimes you to put them down

Sometimes your ride just has had enough. You can see them occasionally in parking lots or on the side of the road. They are sometimes ridden to death, or just to the point of exhaustion and fall over. Often the reason isn't obvious it just happens. It is a sad time when you have to face reality, that point where you have to put them down, losing a trusted and good friend. 

Supposedly you can put your ride down with a single shot, but after looking all over the web I have found no information as to where to shoot it. Does the round go through the engine or the brain?

It's at times like these you wish you could go back in time, back when things were simpler, and there was a method to putting down your ride.