When it comes to pressures, loading manuals are more or less a guide. My barrel, and your barrel, are different. My chamber, your chamber, is different. I do however carefully regard velocity.
A gross example,my Marlin 336. The chamber must have cut with a sausage, it is huge!
I was absolutely unable to reach velocities of 2100 to 2200 fps with a 170 following manual data. There simply was not enough powder in the case. So I had to bump up the loads. If you look at manual data, my loads are clearly above manual maximum.
what I took to CMP Talladega
See where the manual stops for IMR and AA4064
Now, there is some hot data out there, and a maximum load is always trouble. Manuals often show 2900 fps with a 150 in the 30-06. There is one individual on this site who recommend pushing a 150 grain bullet in a
Garand at 3000 fps
, but you know, even in a 26 inch in barrel, I can't get there without issues.
Shot well
but, caused erosion around the firing pin hole.
I cut that load down to 57 grains, and it rolls around 2750 fps. And shoots well.
While nit noids will point out, velocity is not pressure, what is true, the faster something is going, the higher the pressure. I use manual velocities as go and no go guidance because I can measure velocity. Time and again, if my bullets are going faster than manuals, pressure problems occur later. And, something that is true, even when my loads are below manual maximum, once I start encountering blown, leaking primers, I cut the loads.
I also have found, the more you shoot loads, the more you end up cutting them to the point, where you don't have problems.
One day, this load shoots great, no problems
and then pressure problems appear
so, massive load reduction.
