I was aware of 1 and 2, but I had other ideas about 3. That is, I'd figured that the long throat time would allow some pressure to bleed by the bullet before it actually engaged the lands. We're talking about a very short duration of time involved for this to happen. I suppose during the time the bullet is freeboring, gas by-passing the bullet creates a pressure within the barrel itself, which the bullet encounters once it hits the lands. Which in turn would slow it down and raise pressure, however briefly. Is this the idea or is there some other explanation?How to encounter a pressure spike by changing COAL:
1 - Seat the bullet so deep that your nominal load is suddenly a compressed load. Powder-dependent.
2 - Change the COAL so that your "fast high-pressure round" is suddenly jammed way into the lands.
3 - Change the COAL so that your "fast high-pressure round" is suddenly a quarter inch off the lands instead of 0.020" off the lands. The huge increase in throat time can result in pressure spikes.
Very good information throughout the post.