I know this isn't really the topic but I have to commend your courage in taking an armored car job. I'm sorry but you are woefully under-armed for the job you are doing.
In many, if not most countries, armored car crews (as well as private security) carry assault rifles or submachine guns. For some reason in America you are given an old rusty revolver and told "here, guard this 500 grand." I don't even think they issue you guys body armor do they? If you ever get held up, if the guys doing it are even half-way professional, they will have both body armor and semi-auto rifles, maybe assault rifles. Even if you have a shotgun in the back it will be useless against their body armor.
I considered doing this myself but then I realized the only way I'd have a fighting chance is if they let me carry a rifle, which they won't. It's easier for them to just file an insurance claim -- they don't really give a damn about the guards' lives.
Anyway I just wanted to make sure you had taken the danger into account.