Don't have much to add other than I lived with a guy who was shot in the thigh with a G32 at contact distance. The FMJ-FP passed within a few inches of his sciatic nerve. He was around 9-10% body-fat, runner-type build. He walked to his car, and drove to the hospital. If a GSW of that nature cannot disrupt the sciatic nerve, I highly doubt it will do anything to the brain if it hit him in the chest.
If it were causing an increase in pressure, we would note ruptured vessels in the eye on autopsies. Further, we would see venous valve prolapse, quote possibly, as well as other tell-tale signs of "over-pressure" in the circulatory system.
Recoil: Felt-recoil is a function of mass, velocity, and mass of the platform you are launching a projectile from which determines the duration of that recoil.