I am going to offer the idea that the primer is not being struck hard enough. This could be due to excessive headspace, where the sizing die set the shoulder too far back. Could be aggravated by off center firing pin hits, which are not all that uncommon. Or, maybe the primers were not fully seated in the pocket, requiring the firing pin to seat the primer. Maybe you have a weak mainspring.
I have had hangfires and squibs in high mileage revolver. It stuck a bullet in the barrel throat, burnt powder looked like gray cotton candy. Nice indentations on the primer. A new mainspring fixed that.
Bullet lodged in throat, took a screwdriver and hammer to beat it back enough to open cylinder
Primer looked well struck
I also had hangfires in a M1903 35 Whelen. Nice indentations That took a new mainspring, sizing the cases so that there was no clearance, in other words, a slight crush fit, or a zero headspace fit. And I started using Federal primers in 35 Whelen, Federals are the most sensitive primers on the market. That was one 35 Whelen, my 35 Whelen Dumoulin Mauser, I replaced the firing pin with one that had more protrusion. The Dumoulin was not hangfiring, it was misfiring. Primers looked well struck, nice indentations, etc, found a WW1 era firing pin that had more firing pin protrusion, everything is going bang.
This is a two dimensional image of a three dimensional chart, would have liked to see the three dimensional. I believe this was made to compare manufacturability of different primer compounds, so the moisture content is important in the factory, for safety. But still, look at probability of ignition for a dry primer cake. There is an energy input band in which the primer cake won't ignite, then maybe ignites, than fully ignites. Incomplete primer ignition will not completely ignite a powder charge. It takes a good strong flame for complete ignition.
Maybe that is your problem. Check the cartridge case headspace of a fired cartridge against a sized cartridge, if there is too much clearance, that could be your problem.
I have had hangfires and squibs in high mileage revolver. It stuck a bullet in the barrel throat, burnt powder looked like gray cotton candy. Nice indentations on the primer. A new mainspring fixed that.
Bullet lodged in throat, took a screwdriver and hammer to beat it back enough to open cylinder
Primer looked well struck
I also had hangfires in a M1903 35 Whelen. Nice indentations That took a new mainspring, sizing the cases so that there was no clearance, in other words, a slight crush fit, or a zero headspace fit. And I started using Federal primers in 35 Whelen, Federals are the most sensitive primers on the market. That was one 35 Whelen, my 35 Whelen Dumoulin Mauser, I replaced the firing pin with one that had more protrusion. The Dumoulin was not hangfiring, it was misfiring. Primers looked well struck, nice indentations, etc, found a WW1 era firing pin that had more firing pin protrusion, everything is going bang.
This is a two dimensional image of a three dimensional chart, would have liked to see the three dimensional. I believe this was made to compare manufacturability of different primer compounds, so the moisture content is important in the factory, for safety. But still, look at probability of ignition for a dry primer cake. There is an energy input band in which the primer cake won't ignite, then maybe ignites, than fully ignites. Incomplete primer ignition will not completely ignite a powder charge. It takes a good strong flame for complete ignition.
Maybe that is your problem. Check the cartridge case headspace of a fired cartridge against a sized cartridge, if there is too much clearance, that could be your problem.
