I have no doubt that coils have burnt out, but the real question is why. To get more spark out of a coil you have to put more in. And to quote from MSD install instructions, talking about the primary coil wire connections: "During cranking or while the engine is running, very high voltage will be present and no test equipment should be connected."
I believe it was my son whom hooked up an inductive pickup at the + coil and used an "O" scope to look at the voltage and it was 200+.
But that number may be wrong, but it was WAY higher than 12VDC.
Just a point of curiosity really, I have studied magnetism probably more than most, but you could study a small portion of magnetism for a lifetime, and still learn. It is a fascinating phenomenon.