OP you are lucky that hard primers are what you are dealing with.
I have a unused box of 250 rounds of "Professional/commercial grade" .40S&W reloads that are not safe to use. I bought them years ago at a gun show out of state and after a blow out case rupture there useless. I reload now so I pulled a few down to weigh the powder and found that most were 4.9 grains. Which in most of my reloading manuals is around max level. A few weighed 6.8 grains! Yes six point eight grains of powder. The powder is unknown but I suspect it is a Shotgun powder from the looks of it as that was all the rage in 2004. Many shotgun powders are also temperature sensitive to hot days spiking in pressure.
Unless I load it myself I do not use reloads even from friends I reload with.
I have a unused box of 250 rounds of "Professional/commercial grade" .40S&W reloads that are not safe to use. I bought them years ago at a gun show out of state and after a blow out case rupture there useless. I reload now so I pulled a few down to weigh the powder and found that most were 4.9 grains. Which in most of my reloading manuals is around max level. A few weighed 6.8 grains! Yes six point eight grains of powder. The powder is unknown but I suspect it is a Shotgun powder from the looks of it as that was all the rage in 2004. Many shotgun powders are also temperature sensitive to hot days spiking in pressure.
Unless I load it myself I do not use reloads even from friends I reload with.