Hi JMS.
It was the difference between the Quickload and the Manual Data that suprised me. If Quickload predicts that 61 grains is running at maximum but safe pressure it would seem to differ greatly from Lab tested Data in the Manuals. Just how accurate is Quickload?
Yorkie.
I've found QuickLoad to be a very useful
accessory to industry published loads. When deciding on a load, I refer to the industry manuals (either printed or online) and also use QuickLoad as a cross reference. I have manuals by Hornady, Speer, Sierra, Vihtavouri, Hodgdon, Swift, A-Frame and others and in some cases, several editions. What I find is that the manuals tend to become increasingly conservative over time. For example, an older edition might havea load range of, say, 42.0 - 46.0 grains and a later edition reduces that to say 41.0 - 44.0 grains.
In terms of accuracy, QuickLoad's predicted velocities seem to be nearer the mark than the printed manuals' predicted velocities, which are over optimistic (as are the claimed ballistic co-efficients). If you load for several types of ammunition, rather than just one rifle, QuickLoad is worth having. It also comes with QuickTarget for calculating external ballistics, and that's handy. I know you can get apps for mobile phones these days.
What QuickLoad cannot do for you is tell you what pressure
your barrel produces. It can only make a prediction based upon its 'model' barrel. If you want to know what true pressure your particular handload produces, send ten round to the Birmingham Proof House who, for a reasonable fee, will test your ammo and produce a technical report for you. The last time I attended the Proof House's laboratory, which was at least five years ago, the fee was around £65+VAT. The thing to do is prepare three loads of 3 rounds each. Speak with the lab staff. Alternatively, you could buy a PressureTrace kit
RSI - PressureTrace I've got one and it's quite revealing. [You either calibrate your barrel using factory loads or send a sample to the Proof House who will give you an absolute pressure reading.] Even if you don't calibrate the device against a known pressure, if one of your handloads indicates 50 kpsi and then next shows 60 kpsi, that's a real 10 kpsi increase. One of my handloads (with a slow powder in a .30-06) delivered two peak pressures, othe first as the bullet left the chamber and the second occurring as the bullet exited the muzzle. This is now a known phenomenon (see the PresureTrace website) and is cured by using a slightly faster powder.
-JMS