Quick Load - settle a discussion

[savagedasher]

Yep... and is why your outputs are calibrated to nothing, and are "guess-ti-mates" at best.
Oh, but they make a post sound more convincing on the internet...lol

 

[Keith Glasscock]

Unfortunately, the psi figures coming out of QL are, at best, a guess. I've found that the simulation of Varget is not good.

I would approach this a different way. From a materials standpoint, primer pockets do expand during firing - just within the "elastic deformation" range. Ruining a primer pocket is a sign of "plastic deformation" For any material, there is likely a bit of research available on its stress characteristics. Conceivably, one could compute how much pressure is required to deform the primer pocket the .001-.003 it takes to ruin them.

The real answer would require measuring the hardness of the case head, and lots of precise measurements, but you probably could get an estimate at least as accurate as QL that way.

 

[Keith Glasscock]

Now that I've returned from my excursion down the rabbit hole, QL estimates the pressure on my Winchester LP brass as 64,200 PSI. The primer pockets are still good after 6 firings.

 

[savagedasher]

After 50 years of reloading one thing that I found is you never start a load at maximum pressure and work down. And any book when you their maximum you always work up with caution. Seating in the lands start way lower .
I don't care what the book says watch your primers. Larry

 

[dmoran]

Keith -

When comparing my own actual strained gauged pressure test with QL, pressure offset is key to get QL to compare, that is widely dependent on what cartridge, and from one cartridge to another. Even then it can be limited for getting the velocity, pressure, and barrel times to match up to actual's. Fairly easy to get 1 to 2 of the 3 to match up, but getting 2 to 3 is not all that obtainable, with large error at times. More so with Magnums and high pressure cartridges like the PPC and BR cartridges.

This is my experience any how, and why I put little faith in QL predictions to accuracy. But it makes for good reference and starting points, that also works very well for cartridge design (IMO).
Donovan