Well...if you read back a few posts, you'll see where quickload estimates are below the operating pressures of safety for this cartridge...you'll also discover with research, this cartridge is similar in pressures to the 10mm.
Thank you,
Dave
To expand on Stag's and Pond's points, Quick Load also begins to break down at higher pressures, compressed loads, sharp shoulders, small case volumes, and large case volumes. Basically, any time you push any variable toward its limit. Which anyone familiar with numerical interpolation/extrapolation models would expect with a predictive program like this. Quick Load is essentially a big compendium of lots of load data, and merely estimates results for your input based on that source material.
So if your Ring of Fingers round is very similar to 9x23 Winchester, for instance, you could reliably expect accurate predictions for a load within 9x23's range. But if the round is truly unique compared to the data in Quick Load, high order non-linear effects will rapidly degrade the quality of the prediction. I understand that the program is almost, but not entirely useless for 5.7x28 loadings, simply because there is so little data in that part of the numbers map (not surprising, since it is a fairly unique round operating at several extremes, with only a handful of published/tested loads offered)
My next point pertains to the above in bold; No, Dave, you do not know what pressures this round is operating at. At best you can guess, since you have not measured anything that can determine peak pressure at this time (muzzle velocity cannot do this, not unless you have a ton of pressure-tested load data to refer back to; it is a one-way correlation). So if you are convinced this round is truly doing something above and beyond its closest competition (9x23) --even if only a little bit since that round kind of operates on the edge already-- it behooves you to do the *real* scientific measurement that can give you *real* design guidance, so you won't have to fumble in the dark up against hard, uncaring, and abrupt limitations of metallurgy.
FWIW, measuring your muzzle velocity from different barrel lengths and powder charges can probably yield a decent extrapolation of peak pressure, especially if you have a similar round to compare to with its own test data. Failing that, a Thompson Contender and ported barrel with pressure guages is the only way to know what you are doing.
But hey, that's why they're called "wild cats" --the designers *don't* know what they're doing, so the whole thinng carries the same type of risk as home distilling (blindness), but the rest of the world may eventually accept the idea after enough years of people not hurting themselves repeating your experiments (another important component of real, hard science)
TCB
