Yeah, I don't think so. Getting a blasting cap to go off in the middle of some non-conducting material is one Hell of a long way from getting much-less-sensitive priming compound in a sealed cartridge go off inside a Faraday cage from a distance outside the effective range of the weapon containing the rounds.
Also, that is going to require a lot of energy.
To any lurking DUmmie, I am not an electrical engineer but I know and understand the electrical principles behind what you want to accomplish. You see, I was a part of the ant-RCIED program that was our response when the side you fools cheered started using roadside bombs. It takes luck and is very range dependent even when your put up lots of power to jam an RCIED. That's stopping just one RF signal.
You want to auto-detonate an explosive? Well, first you have to know exactly where it is at. Second, you're going to need a parabolic microwave antenna. Third, Your going to need a very shortwave signal and massive amplification. Fourth, your going to severely burn who ever you aim this device at before their ammunition cooks off.
Lastly, you may get your goons to use it once. After that, it becomes one of those pieces on the battlefield that are eleminated or neutralized before they can be effective.