Miller; Thank you for taking the time and effort to explain this complex concept of recoil and the relation to pressure to us/me. I appreciate it/you. So, am I correct to say, recoil has no or very little relationship to MAX pressure but is more related to total pressure which is defined by that area under the pressure curve?
That's it Buzz. The velocity is as you said the result of the Force applied to the load & of course as you also said that Force is generated by pressure.
Also, some facts worthy of consideration is the total time from ignition to the load exiting the muzzle is around .003 of a second will vary just a wee bit according to load).
Total movement of the gun during that .003 second is proportional to the weight of the load & the weight of the gun. In the example, I cited above where the total load weight was 0.08 of a pound & fired from a 6-pound gun the gun movement at the time of exit would be about 5/16 inch. The rest of the movement is the result of the Inertia given it in that brief period.
It is also well to keep in mind that Fast vs Slow is all relative. The entire range of powders suitable for shotguns is a rather small range. They are all extremely Fast if you compare them to burning an old worn out cotton batting mattress.
They are all Extremely Slow if you compare them to the Detonation of a high explosive.
