Larry;
Either I totally goofed in what I said or you misread it badly. Certainly after the max peak is reached the pressure begins to fall & does so continuously till the load exits the muzzle. The lower & higher were meant to be in comparison to the other load. If two loads give the same ballistics at different pressures the one which began with the lowest max chamber pressure will have the highest barrel pressure. Exact curves will of course vary with different loads, but about 4" from the breech is the general vicinity where the two curves will cross.
Thus to use the same two examples I used before if the MWT is out around 18"-24" from the breech the load which had 8K max chamber pressure will have higher pressure out at the MWT area than will the load which started with 10K max chamber pressure. Certainly in both cases the pressure Out there is going to be much lower than the max chamber pressure, it don't increase anywhere after th peak unless it hits an obstruction.
The point is though assuming a sound gun with ample wall thickness in the breech area with a thin area Down the barrel a ways you are not doing it any favor by lowering the chamber pressure if you do so without reducing overall ballistics of the load.
Lets say for example again that the proof of the gun is good for a load giving that 10k PSI max pressure. Say you have a load which pushes 1oz shot out a 1200 FPS at that pressure. That load will give the lowest pressure "Down There at the Thin Spot" than any load pushing that same 1oz of shot out @ 1200 FPS but with less chamber pressure than 10K PSI.
