In terms of hardness--that is the for resistance to primer indentation, what would a ranking of brands be from hardest to softest? IOW, would one brand be soft enough to cause a firing pin to drag upon opening, and another be hard enough for smoother operation...how would you rank them? Steve

WW primers cause firing pin drag in my William Evans 12 bore, factory target shells or reloads with WW 209 primers, the gun is really hard to open, skid marks on fired primers
Shot some Fiocchi target loads and WW AA hulls loasded with 616 primers, problem vanished.
In this gun, it seems that WW primers are too soft and the firing pins hang up

I found Remington primers in both loaded Remingtion Heavy Shot shells and as reloading components would occasionally not fire in one barel of a Winchester M23 Heavy Duck. Other amunition and primers did not suffer from this gun.

I had the gun serviced adn no more problems. It was a small sample set but others told of similar problems.

Diassemble a primer, or a few different ones. Actually take the battery cup out and check it with a magnet; you'l find most, or all current cups are steel. Up until recent years, (70s maybe) the battery cups were brass, and there were very few misfire problems, or primer dragging making hard opening of some guns without rebounding hammers. Today you have to experiment and find a primer/shell that is soft enough to fire reliably, and hard enough to not drag. From my experience, Fiocchi primers are hardest and cause most misfires in old guns not designed for them. I do not mean to bad-mouth Fiocchi, just state my experience. Try some old paper vintage shells and see how they perform.

It should go w/o saying that disassembly of a live primer is NOT to be undertaken under ANY circumstances.

I've had a lot of misfires, light strikes w/ Cheddite shotgun primers . Older guns (all pre WW2), all different types, gauges & makes. A second strike on the pre-enjoyed shell will set 'er off.

Win & Fed 209 no ignition problems. The Winchester209 seem soft and will drag if the (SxS) action is out of time a bit and the hammers don't lift immediately with the opening of the bbl.

Not really the fault of the primers,,but the problem can be 'fixed' for the short term by finding a primer with a harder material so the FP doesn't bury itself into it.

Cheddites'd probably fix you up,,but the gun might not go bang all the time either.
When they're bad,,it's 5+ 'clicks' out of 50 rounds. That's annoying.

Just my experience...

BTW, it always goes bang...it's just that the firing pin really makes a deep impression which sometimes drags as well. Hate to shorten the firing pin, especially since I just paid to have it all cleaned. (had not fired it prior to service cleaning) Steve

I've been using mostly Cheddites in reloading for quite some time now. Both 12 and 20, mostly in vintage doubles. Can't remember the last misfire I've had, and no problems with primer dragging. That being said, vintage doubles can be problematic for all sorts of reasons. A friend was shooting a Lefever yesterday with reloaded Federals, all sorts of problems opening the gun after firing. I gave him a couple of my STS reloads, no problems. Not a primer drag problem, but obvious difference in rim thickness, the STS being thinner.