How would you go about developing a load using a powder for which there are no published loads? Or would you never do that?
For example, I've been working on loads for a handgun cartridge. I found the faster pistol powders were fine for light loads but left a lot to be desired. A medium burn shotgun powder delivers substantially more velocity with low SD. Laddering up, I found the best results were actually slightly over the published max, and with a shorter OAL. I know my best load is over the pressure spec, but I don't want to settle for the results I got within the published parameters. There's load data published for that shotgun powder, but there are other powders above and below it on the burn rate charts. It's tempting to ladder to slightly slower and faster powders, but without PSI data from a transducer chamber, I could only estimate what load in grains of powder would be the maximum. The only empirical data I'd have is chrono measurements. I know with rifle cartridges we can look for pressure signs, but this is handgun where the limit is less than 20,000psi. Those pressures are never going deform the primer or even make extraction hard or really show any signs at all.
It seems like load development without measuring the pressure is lame unless one just wants light loads or to follow someone else's work out of a book.
For example, I've been working on loads for a handgun cartridge. I found the faster pistol powders were fine for light loads but left a lot to be desired. A medium burn shotgun powder delivers substantially more velocity with low SD. Laddering up, I found the best results were actually slightly over the published max, and with a shorter OAL. I know my best load is over the pressure spec, but I don't want to settle for the results I got within the published parameters. There's load data published for that shotgun powder, but there are other powders above and below it on the burn rate charts. It's tempting to ladder to slightly slower and faster powders, but without PSI data from a transducer chamber, I could only estimate what load in grains of powder would be the maximum. The only empirical data I'd have is chrono measurements. I know with rifle cartridges we can look for pressure signs, but this is handgun where the limit is less than 20,000psi. Those pressures are never going deform the primer or even make extraction hard or really show any signs at all.
It seems like load development without measuring the pressure is lame unless one just wants light loads or to follow someone else's work out of a book.