[Brian Pfleuger]

There are two primary powder related factors in recoil. The one is powder weight, which is obvious, the other relates to burn speed... muzzle pressure. The bullet's exit of the barrel essentially "uncorks" a very, very high-pressure bottle. You have a rocket in your hands, at that moment. The higher the pressure is at the instant that the barrel is "uncorked", the higher the resultant "rocket effect". The two effects work together. A faster powder will reach max pressure at a lower charge weight. It burns faster and will have a lower muzzle pressure. So, lower pressure AND lower weight.... less recoil. The rocket effect percentage of recoil can be very significant. As much as 1/3rd, even 1/2, of total recoil.