A friend of mine wanted to go shooting after work yesterday. I had the gun in teh case in my trunk, but would have had to stop and pick up some ammo. I started thinking that maybe I should jsut keep a box in the car for such an occasion, but then I wondered if it could be dangerous in the summertime. Is it possible for it to get hot enough in the car to cook off a round or two?
American Rifleman did a series of articles several years back in which they attempted to "cook off" some .30-06 rounds using a propane torch, a screen made up of corrugated paper board, and then bullet resistant glass through which to view the whole process. The best they managed to do was to melt the lead bullets and ignite to powder inside in a Pfffttt! burning fashion in most cases. The few they managed to "cook off" had the flame applied directly to the primers, and even then, didn't manage to penetrate a full thickness of "cardboard" box material. I don't think I'd be overly concerned about small quantities of shoulder held weapon ammo "cooking off", althogh I do know that one CAN, if persistent, "cook off" .22 rounds (no, I'm not going to repeat
that story), but I suspect it is because of the way the primer is dispersed around the rim, and perhaps in the composition of the primer compound itself. Either way, it takes MUCH higher temps than any car other that the Devil's is likely to be exposed to.
What I'd be more concerned about is having loose ammo in my vehicle if you ever have to go onto Weyerhaeuser, Conoco, UniRoyal (or rather the folks who bought UniRoyal out) or other's property on business. All of the above, and I'm sure many others, have a strict policy on the possession of firearms or ammunition on their properties. As a frequent reloader, shooter (former competitive and incorrigible plinker) I constantly had loose ammo in my glove box, etc. All perfectly legal in my state, UNTIL I drove onto one of these prohibited areas.