I didn't have the gumption to read 13 pages of opinion, but here is a bit of info from an aero engineer specializing in propulsion. Yes, burnt powder and gas IS an ejecta. You figure the powder weight and use 50% more velocity than the bullet/shot velocity up to a maximum of 4000 Ft/sec. Why? Because some fine soul measured it empirically and back calculated how to do it analytically. It was long before Sherman Bell, so it wasn't him. Lots of things enter into related calculations. For example, an increase in temperatures will increase pressure but decrease burn time so that the total impulse will remain the same.

Now felt recoil is a great opinion subject. There was the guy in Texas who fired his Weatherby rifle from a tree blind. The Italian maker of the stock forgot to put a pin through the wrist and the poorly grained wood in the wrist broke in two and the front part of the gun came back and cold cocked the shooter in the eye and nose. Hmmm, what was the FELT recoil? Next to nothing. There was less recoil on the rifle butt, and the rendering unconscious for 5 hours sort of dissipated the felt recoil, at least for 5 hours.

Now a great topic would be the design modifications to gunstocks to lessen felt recoil. Let's see, some variables would be area of butt, type of recoil pad, LOP, cast, drop, pitch, whatever you call the changing of the angle of butt relative to longitudinal axis, straightness of stock, weight, counter weights,.. who can add another dozen or so things?

Another interesting subject might be listing the things that effect felt recoil like...type and amount of adult beverage consumed the night before, amount of time spent teaching your son how to throw a fast ball and curve the day before, amount of aspirin consumed following the aforementioned sports, etc. How about a couple hundred suggestions on this topic?