....At peak pressure, the ejecta will be accelerating at its highest rate (g-force), unless it's constrained from movement. The peak acceleration of the ejecta will coincide with the peak acceleration of the firearm in the opposite direction (not the peak velocity of the firearm). Those recoil charts in Drew's reference tell a lot.
The peak rate of acceleration is necessarily higher in the rifle example because we know the ejecta separates from the gun at a significantly higher velocity. But, the peak force at the moment of highest acceleration is no more than it takes for the smaller bore and lighter ejecta mass to overcome its resistance.
In identical guns in every way, including the total force of the ejecta clearing the muzzle, the rifle will have some higher peak force. But, only to the extent that the area under the graph for total force can be identical to a slower, heavier shotgun load over a shorter period of time.
Doc Drew's article by Hall took pains to assure constants in the devise he used to record the measurements, but he also wanted to document that the ammo he used was a constant. His conclusion was that he could test a different gun and predict differences in how recoil would be perceived.
I never realized that type of recoil study was available, but all else being equal, what did it reveal about differences in felt recoil between heavier/slower and lighter/faster equal energy loads? If peaks and totals happen over very short periods of time, how discriminating could the human be. It seems like Hall measured a vertical rise component, that may be interesting in the longer duration of a slower shotgun load.
Maybe, more pop in the cheek would be perceived as more felt recoil than accelerating the gun at a higher rate directed more inline with the shoulder. But, the conclusion was that the magnum rifle would necessarily generate more felt recoil due to a higher peak contained within the total duration of firing the ejecta. Only in light hearted fun Chuck, and I remain open to understanding what I'm missing in those recoil charts.
