[eeyore]

Originally Posted by Jim Ford

A high velocity rifle bullet will generate a shock wave in a drum of fluid that will rupture the drum and partially vaporise the fluid.

Jim

good point - but outside of holywood (and war zones) cars arent routinely hit by high velocity rifle fire - they are however routinely crashed into each other and petrol spills in these situations very rarely ignite , whereas a cloud of flamable hydrogen would pose a far higher risk