Also, I'll point out that I understand what Paul Harrel was thinking about using JHPs from 50 round boxes. So lets skip past Job 1 except he seemed to think accuracy can suffer in the higher velocity, higher priced loads. To a lesser extent, if we trust the USPSA shooters to know what they're doing with Major 9, adding a safety cushion of 5 PF above 165 PF a 124 gr bullet will need 1371 FPS to reach 170 PF. 2 very important things here: usually a custom pistol is used, with mostly 1911s where longer chambers allow loads to be longer than the SAAMI spec for Max OACL really intended for FMJ while the gamers are using JHPs. These barrels typically have a slower rifling twist of 1 in 16" rather than the 1 in 10" typical of 9mm service pistols. Obviously they believe the slower twist results in greater accuracy. IMO, the 1 in 10" twist is very well suited to supersonic 147 gr loads. As I mentioned before, supersonic velocity at sea level is usually stated to be 1118 FPS or very near to it. There really isn't much need in pushing them faster when excessive velocity will cause jacket/core separation. I ain't gonna touch that one except to say that some bullets like the Golden Saber that can separate, probably the most in my experience testing JHPs, their brass jacket still penetrates very close to the depth of the core.
As far as following the lead of LE. That works for me so long as it's an agency like the DPS rather than the FBI. The Hornady 135 gr. +P Critical Duty was mentioned and maybe I've already posted on that here or elsewhere. At a factory spec of 1110 FPS, I really don't get the +P rating. Unfortunately, and the loads I chrono'd were gifts to my SPs friend by a DPS trooper and fired from a tube 1/2" longer than Hornady's 4" test barrel, velocity ran 1090 FPS. Expansion would be better from their XTP if they made one at 135 grs. Reducing velocity to get deeper penetration due to less expansion is a road I won't be traveling.
Neither am I concerned about 15 - 18" of penetration. I, myself, being a fairly large human, am not that thick from front to back, and have always practiced C.O.M. shots. You simply can not practice for every contingency except the mindset of shooting until the threat is over. 12" of penetration works for me, and penetration from the same load after 4 layers of denim is going to be deeper anyway. As far as the QAS system, a stop means the aggressor is stopped within 30 seconds, and subsequently it shows greater results with each successive round fired. That's a good deal different than the OSS data collected by Marshall & Sanow and over those 900 loads Charles Schwartz has tested, he rates JHPs being very good at 70% for the first round. Very good loads get to 98% by the third, 99% by the 4th. Becuase of the extent that exponents in math can reach by a scientific calculator or computer, you could be shooting for days before you got to 100%. Realistically impossible. The percentage for 3 shots usually tells me what I want to know.
But because that 1 load failed to reach the heart by a very few millimeters, and as I've mentioned, a 115 gr JHP in 9mm at 1135 FPS doesn't even reach the very minimum I would mention for a load being considered, the FBI has had an obsession with deep penetration. They would do well, IMO, to remember what happened with a number of agencies just after Miami 1986 when the first 147 gr JHPs became available, and very much loaded subsonic. They rarely expanded enough, and cases of bystanders being struck by over-penetrating loads resulted in several personal injury lawsuits. Almost immediately, Peter Pi of Cor-Bon found a better solution by pushing those same 147 gr JHPs just barely supersonic at 1125 FPS with a +P designation.
So, if any of you are game and have a chronograph. Check the velocity at the same distance to the first water vessel you use. Recover the bullet and weigh its mass, and depending on its final shape, the calculation for average diameter in cases where the JHP expands in 6 petals, you'll need the 3 outside diameters and the 3 between the petals. The WIN 147 gr JHP I tested last week and reported on in the reloading section gave very symmetrical, nearly round expansion with maybe only a couple of differences in the expanded dia. I can run those stats in the Q-Model to give a number of different values starting with the predicted depth of penetration almost identical to the depth the same bullet will penetrate in the real FBI test gel. Other values are wound mass and wound volume. Energy expended in the 1st - 15th centimeter. Power in kW and now with the latest version, even the Ballistic Pressure Wave in PSI. So, whatever doctrine you subscribe to, it is very likely predicted in the Q-Model program. 900 loads compared with an accuracy rate that's pretty exceptional, IMO, at 95%+.
In my own estimation, I've always put a lot of emphasis on what is described as the mThor value or Delta E15 with the proper symbol used rather than the word delta being typed, energy expended in the 1st - 15th centimeter. There is a connection between that value and the power rating in kiloWatts. Pretty decent power values come at around 110 kW and up to 170 kW with some of my better 9mm loads recently. Depth of penetration will be 12" mimimum in bare gel or very close to it while I strongly suspect that this is about how rapidly the JHP expands while still penetrating 12". For me, it's pretty hard science and very few prediction tools can be realistically higher than a reliability factor of 95%+.
Sorry, I did it again!
Anything that can be corrupted by man; will be corrupted.
The Lord is my shepherd; I shall not want . . .