"But even I don't worry too much about primers. They seem mean and scary, but in reality they're fairly weak."
Really? Well in the interest of disspelling that myth, I'll tell of my experience with primers.
Now for the rest of the story........
I hesitate to tell this, as it was a dumb stunt on my part, but it fits right into this thread.
Early on into my reloading career, I was given a big pail of military 30-06 cases. They were all primed with an unknown primer, they had been stored in some guys garage under less that ideal conditions.
I didn't want to trust them for regular loads, my dads rifle wasn't to be used to just fire them, so I set off to deprime live primers. Not wanting to use the FL die in my rock chucker, I made a military decapper, I turned it down in a lathe from a 5/16 th allen wrench. I then used the shell holder for a base to whack the deprimer punch with a ball peen hammer.
At first I used the bench for this, after about 30, I was getting tired of leaning forward to smack the punch. I moved the set-up to my leg, and proceeded to work more comfortably. THE FIRST ONE WENT OFF!
Maybe it was the first one to have an active primer in it, but it sure hurt. A hole in my jeans corresponded to a hole in my leg, not much blood but a kind of deep numb pain.
I put a band-aid on the wound, went and told dad what had happened, we decided to wait till the next morning to go to the hospital ER.
X-rays showed the primer cup had gone 1.5 inches into the muscle, with the separated anvil ½ inch behind it. The doc froze the area, retrieved the anvil without too much trouble, but had to use a fluoroscope to find the cup.
They were about to call the cops, thinking I had been shot. I tried to explain about primers and reloading, but they didn't know what I was saying. Finally one of the tech orderlies heard what was going on, HE was a reloader also, took a look at the x-ray and said "cool it" to the doc. He then had to hear the story himself, the forth time I had told it in less than an hour!
So Kayser, a primer don’t have much force? it not only goes bang but with considerable power! The quad muscle on a 22 year old leg is pretty dense. For the primer to have penetrated that far in dense muscle, it had to have plenty of power. Also considering a very loose fit in the shell holder and the leaking around the punch, it did a lot of damage!
BTW I just turned 60, so put the rookie comments away. Like I said a dumb move, but it sure gave me a pile of respect for the force contained in a primer.
That said, using a FL die or a de-capper die to slowly push out a live primer is very safe. A primer reacts to percussion, meaning it has to be hit HARD with a pointed firing pin, while the anvil is bottomed out in the primer pocket and the shell is held tightly in a chamber.