LRRPF52 Wrote:I dont have any emotions about QuickLoad. I just recognize that the developer(s) never had 6.5 Grendel pressure trace data with a test breech, and that their generated peak and subsequent down-barrel pressure levels are starting with peak pressured that are 9,000-13,000psi different from actual calibrated test breeches with this cartridge.
So not only are the chamber pressure models invalid and not useful, but the predicted port pressure values are way off too.
If you took available test breech data and programmed it into QL for 6.5 Grendel, as well as down-barrel piezoelectric measurements, and generated a nice data set that way, then QL/6.5 Grendel would be very useful for this cartridge. Whatever modeling they have in the program is basically useless though and invalid, especially as a diagnostic tool in this situation.
I would agree that peak pressure modeling is iffy at best for both 6.5 and .223, but since we already know what the expected peak pressure is we aren't calculating it, we are simply following a predicted curve.
You can think of it this way. With your experience, take a piece of graph paper and approximate the pressure curve and designate the peak as 52kpsi by simply drawing it. Now place the positions of gas ports relative to pressure curve. You will get the exact same visual data, pressure is too high. In essence you are quickload in modeling. Accuracy here does not matter, and data is still valid enough for diagnostics.
Im not saying that it's any more accurate than just eyeballing it... but since the delta is so big, it's pretty easy to do and accurate enough. Microscopic levels of resolution and precision are not needed in a case where simple demonstration of a past event with no consequence to gather theoretical data to support a postulation. Been a good read so far though.