Larry;
IF you could simply understand what you read then you really would not have had to ask such a question. It all started from the knowledge that, yes max pressure falls off fast. However, it still takes the same amount of total force to get that oz of shot out the end of the barrel at 1200 fps, or any other load you desire to make a comparison with.
The whole point was if you have a gun with thin barrels near the muzzle, even if you drop the peak pressure from 10K to 5K, you have not lowered the total force applied, just redistributed it. You thus have not truly done that gun with thin walls near the muzzle a favor by lowering the peak pressure, you have actually slightly increased the pressure down under the thin spot.
As Force = Pressure times Area this also explains the comparison of firing the same load to the same velocity from guns of different gauges. Area of a gun's bore is proportional to the square of their diameters, thus the pressure is also proportional to the area.
Using nominal bore diameters (.729/.615) = 1.405. For brevity, I simply called it a 40% increase in area for the 12 over the 20. Therefore if you fire the same 1oz of shot to 1200 fps from both gauges TOTAL Average Pressure for the length of the barrel will be 40% higher in the 20 gauge.
Once again this has absolutely NOTHING at all to do with Max Peak Pressure regardless of how many shells were tested to list the AVERAGE. This all based upon "Proven" Scientific Facts & actually applies to many fields other than just guns where pressure is involved, including internal combustion engines, hydraulics, etc.
Until some time as you get it through your head that there is a lot involved in shotgun ballistics than JUST the Max Peak Pressure then I suppose you will never come to an understanding of this. In the meantime, if you so desire just go on with your non-related blurbs which mostly gives the appearance you have little understanding of mathematical principles. Personally, I think, Perhaps, the appearance is not deceiving.
