Does the pressure have to be sudden or can it be relatively slower than a firing pin?
Say for instance, I set primers on the ground with a nail in a position to sit on them as soon as weight is applied, would they go off if someone stepped on them? How much weight do you think would be needed?
Good for a prank or would it blow a foot off?How much pressure does it take to set off a shotgun primer?
The pressure should be sudden. The firing pin strikes the bottom of the primer, compressing the sensitive primer powder between two metal surfaces inside the primer assembly (see diagram for a Berdan primer in link below). If there isn't enough force added instantaneously, then there won't be enough energy transfer to ignite the primer, and the primer compound will likely just be packed tighter together. That said, you never know, it might just go off when compressed slowly anyhow, or it might just become more dangerous and unpredictable.
Primer powders are very sensitive and very volatile compounds. A friend of mine lost his eyebrows reloading ammo because of static electricity from dragging his feet across a mat on the floor. Primers really shouldn't be treated as toys or gag items, they're explosives and need to only be treated with upmost respect. Please take care.
http://www.ojp.usdoj.gov/nij/training/fiHow much pressure does it take to set off a shotgun primer?
that would blow a foot off
