Mark, thanks for the excellent reply! I know it took a while to create, and I appreciate it.
I was not familiar with the E-tip, and I will definitely be looking into it.
I have shot both the standard 180 grain Partition Soft Point and the 180 grain Partition Protected Point. The 180 gr. Protected Point was designed to address the problem of tip deformation in magnum magazines which you spoke of. But it has a lot lower BC, only .361 compared to the regular partition's .474. It has a slightly more forward bulge to its ogive, different profile, and a flatter tip.
Left to right, the Partition Protected Point next to a regular Partition, and a regular Partition that has been through the recoil of my rifle in its (plastic!) magazine, and has its tip all smeared around.
The felt bedding I was referring to was actually bedding in forends which firmly touched the barrel, not action bedding. I've seen some old english rifles with it, and my old Ruger M77 has some felt between the forend and the barrel too. I think its purpose was to dampen those waves, which are probably the same thing as what you are calling the harmonics.
THe Quickload program actually allows you to change its default value for pretty much everything - such things as case capacity, cartridge COAL, bullet length, etc. So, if you change brass and the lapua has 2 grains more case capacity, you can change that value. There is even a sort of "fudge factor" you can play with to adjust the program's predictions to the actual range performance you are getting. You can even modify the powder data files with all sorts of exotic stuff dealing with burn rate and several other factors. It was written by a German powder engineer and was originally for modeling new light antiaircraft cannon shells! It has preset data (which can be modified) for every bullet i have ever looked for, literally hundreds of bullets from every makerr you ahve ever heard of and a few you havent; about 200 cartridge files preset for COAL, case capacity, max. pressure, etc; and data for every powder made in the world. It is really remarkable what you can do with it.
For example, when I was wildcatting the .30-25 WSSM, I actually modified the 25 WSSM data file to handle a .308 bullet, with same COAL and correct shoulder angle and neck length for my chamber. I got .30-06 +P velocities with short to medium length bullets up to 180 grain, out of an AR15 lower. It was a heck of a learning experience! There was literally zero data for this wildcat so I had to start from scratch, measuring case capacity after modifying cases, that sort of thing. But the program took me right to the sweet spots. (until the weather got to 105 degrees at the range. That really messed with powder burn rates!)
Science commercial: Believe it or not, the speed of sound varies with the medium it is passing through. In air at sea level with humidity at 70% it is 1100 or so fps. At altitude it is lower. In water it is vastly different, as it is in rock, steel, glass etc.
Whatever, it doesn't matter whether it is a speed of sound in steel shockwave or harmonics or little elves with hammers that make there be accuracy nodes in a given powder/bullet/barrel/temperature setup; what matters is the OBT calculator can direct you to the barrel time best suited for your barrel length, and then QL can give you a range of powders to get there, within safe limits.
Of course so can shooting a ladder, or better yet the Optimal Charge Weight method, which takes into account barrel heating as you go through the test better. A lot easier than all the tech stuff I play with as well! But it keeps me off the streets....
Again my thanks for the tip about E-Tips, and for your advice.