I have been reloading for many years and thousands of rounds loaded up. Today I got my first primer activated while inserting into a new brass case. There wasn't any excess pressure on this case/primer compared to 200 others completed prior to the light-Off. Of course it startled the heck out of me. No damage to any items around the area and the fired off case shows no damage or warping from the loader inserting the case. If you look at the primer (of course there is not dimple from being struck) it looks as flat and normal as the others. The primers being used where Winchester SRP. I suspect the anvil was not properly installed or excess material in this one primer. Go figure!