Few (maybe several) years back when some guys were running Federal Gold Medal at the smallbore matches some folks encountered misfires. They'd recock and try again but some still wouldn't go. This is especially annoying in a custom match barrel as many won't eject an unfired round due to the amount of bullet engraving present as set up by the smith. They had to dig them out with a screwdriver.
They would save the problem rounds and later pull the bullets and dump the powder onto a white piece of paper to look for primer material in the powder. They would also look down into the case with a flashlight to verify that the round had a ring of primer in the bottom.
At this time Federal's GM primer compound was green and easy to see if it had shattered from the firing pin strike as flakes of green would be seen in the dumped powder. Federal had two problems, most prevolent was no primer compound in some rounds and to a lesser extent insensitive primer compound.