Since I'm a nerd, I had to play around with the equations. Newton's 2nd law: Force = mass X acceleration. Moving things around algebraically, we get:

acceleration = Force / mass.

Another useful equation is for pressure: Pressure = Force / Area. Moving stuff around again, we get

Force = Pressure X Area. If we plug this equation for Force into the first equation, we have a new equation that states:

acceleration = (Pressure X Area) / mass.

acceleration in this case is the initial acceleration of the projectile. We know also from Newton that "every action has an equal and opposite reaction." So the acceleration imposed on the projectile will also be opposed by the mass of the firearm, and your hands/arms/shoulders. I'm looking at this from a 30,000 ft view, so all this is not "exact", but simplified enough that I can make calculations anyways...

I converted all the units to metric because it's simpler for me to work in metric units. Using Winchester's published reload data that GT4point6 provided, I calculated the instantaneous acceleration resulting from the peak published pressure.

acceleration = (Pressure X Area) / mass:

For the 115 grain projectile, with a peak pressure of 29,400 cup, the acceleration equals 19.27 gram-meters/second^2

For the 147 grain projectile, with a peak pressure of 27,900 cup, the acceleration equals 14.23 gram-meters/second^2

I love it when theory and the "real world" agree.

NOTE: all the above is theoretical, and is nowhere near exact...

Now I'm gonna have to do this for 124 grain projectiles. That's what I shoot!