Originally Posted by
MostlyLeverGuns
Pressure inside the case is equal on all surfaces within the case, pressure on the sides of the bullet are the same as the pressure against the base, the bullet cannot rivet from pressure only on the base. Hitting the base of a bullet with a hammer yes, gas pressure inside a container, not so much. Bullets may obturate or upset when the bullet hits the rifling, but this different from riveting. When loading the the 300 Win Mag and 300 Savage, bullet shanks and gas checks commonly extend beyond the neck and accuracy can be very good. Depending on many variables, powder, pressure level, bullet fit, some heat/pressure damage can affect the part of the bullet exposed to the powder gases above the gas check but this is not usually a problem until velocity and pressure is above 'usual' cast bullet range (1800-2000+ fps). Mostly such problems show up as loss of accuracy noticed well beyond 150-200 yards.