I'm waiting on a couple of paydays, then QL will be on my own computer. I will learn it inside and out, and may ask you some about it more then. I know it does a lot of things. You can also customize it to your brass capacity too which can greatly affect pressure.
From your above post, you seem to have a handle on velocity vs. pressure, and even better (something some handloaders never grasp) is the effect of burn rate on pressure.
I write on online BB's a lot about the .280Rem and the loading I do. Most often I'm told I'm loading way too hot. I tell them I've loaded that way for years with no probs...they say my time is coming one day. Now with QL I have something to back up what I say is safe, and out come the computer software poo-poo'ers. Well, let me tell ya. NASA doesn't shoot rocket after rocket to get the actual data for a real launch, they use prediction software like QL. It's good, tested, solid technology. It works.
I love reading people say "I'm at book max, and it's 200 fps slower...this data is way too optimistic." No, you just don't understand how to read it. They all know that lots of powder can vary, sometimes greatly, yet they think they're supposed to get the same velocity with the exact same powder charge and bullet. Why?
I load this way. I'll use my .280 as an example. Nosler data says I can get 3150 with 57grs of R-19 in a 26" bbl. Hornady says with their 139 and 57.4grs of R-19 I can get over 3000fps in a 24" bbl (Hornady doesn't give exact velocity, they step theirs ever 100fps). Now I got two sources telling me that 139/140 class bullets and R-19 can get between 3000-3100fps in a 24" bbl. (I figure the loss of @ 50-75fps from Nosler's 26" to my 24" bbl and QL bears that out along with other data I see online.) Now, I start my loading by working up from abut 55 grs of R-19. I know that all .280 data is produced at 60K psi. I know the SAAMI for the .270Win is 65K psi, so it's safe to load it up to .270 pressures if I want, or keep it down to 60K and have that extra cushion. I load up to .270 pressures. So basically, I get back the 50-75fps I lost with Nosler's 26" bbl. Now, I simply work up to my target velocity, and the number of grains of powder are only used to get me a reference for a starting point, and if I am at 3100-3150 when I hit 57 grains, then I'm at max. If I hit 3100-3150 at 56 grains I'm at max. If it take me 59 grains (which it does in my
then that is max regardless of the listed max powder charge in the book. The "real listed max" is the max velocity. And now, as a final check I consult QL. It tells me my velocity with the 140 BT is around 62K psi but takes over 60grs of R-19 to get it. (why the powder charge is not the way to look at QL) The pressure is even lower with the 139 Hornady due to shorter bearing surface. So, all the data I have indicates that I'm safely in the good on pressure at velocities many say you can't achieve. When you run the numbers using the faster burning powders many of these folks use, then you see why. Even stepping up in burn rate just a tad to H4350, the same velocity gives as much as 2K psi more pressure. And to the other end, R-22 will give about 2K psi less pressure at the same velocity as R-19. In fact some data I have here on my work computer that someone sent me suggest that you can run the 139 Hornady over 3100fps in a 22" bbl and still be under 65K psi. Many loaders that simply look at book data will tell you that's impossible and asking for a nuclear holocaust! You suggested, and I concur, you must match the powder to the bullet wt and case capacity, and if you do, you can get great results.
I also concur with the original poster in that many times people think they see pressure signs, when in fact they're misleading. The oversized firing pin hole making cratered primers is a classic example. A rough edge on the bolt face creating "shiny spots" is another. Even flattened primers can lie, as the different manufacturers have greatly differing hardness, and many factory offerings flatten primers.