Another consideration before comparing recoil of vintage loads with modern loads would be the weight of powder.
45-49 grains of bulk smokeless vs 22-25 modern powder grains for a 'super pigeon' load would seem to push the recoil, as calculated by a computer recoil calculator, well into the 'ouch' zone.
It's not a great increase in ejecta weight, but that's all transformed into gas at a much higher velocity..... thus the recoil increase as shown by the computer of 25-30%.
If I'm missing something, what is it?
This mystified me too, Shotgunjones... until I saw your subsequent post. I initially found it hard to believe that a mere 20-24 gr. increase in ejecta weight would generate 25-30% more recoil... all else being equal.
Then I saw that your calculation for the modern smokeless load was done for an 8.4 lb. gun, and the calculation for the bulk smokeless load was done for a gun nearly a full pound lighter. You did not provide the velocity for the bulk smokeless load. Do the math for guns of equal weight and loads of equal velocity, and the difference in recoil won't be nearly as much.
