9,150 to 12,650 psi 15 inches from the breech face (which, by the way, is not where an M14 gas port is, it's 13.957) is the specified port pressure.
I see no reason to not believe the info Lysander provided, so that's what I'll use for my example. QuickLOAD uses projectile travel in the pressure graph, so 13 inches of projectile travel should be approximately 15 inches from the breech face.
41.7 grains of Varget in a case with 56.12 gr H2O capacity driving a 168 grain A-Max loaded to 2.820" OAL should give approximately 2500 fps from a 22" barrel. It will have approximately 13,338 psi at 15" from the breech face. This is approximately 5.44% above the recommended psi range.
39.5 grains of powder, all else the same, is the point at which the psi should be 12,520 psi...and therefore fully within the recommended range. The predicted velocity is 2385 fps.
You may be thinking that Ramshot TAC, which is show on Hodgdon's burn rate chart to be very slightly faster than H and IMR 4895 to be ideal. When driving the same A-Max as above, reaching 2500 fps from 42.9 grains indicates 13,534 at 15" from the breech face.
40.9 grains of IMR 4895, with all the above unchanged, should be enough to achieve the same 2500 fps from the 22" barrel. The projected psi at 15" of projectile travel is.........14,026. Hmmmm, how can that be?
The projected chamber pressure for all of the above loads is at or below 50,000 psi. If you want numbers using a specific chamber pressure, those can easily be generated.