why is cast loading much slower and lower in velocity rather than the jacketed? i gather the fact that leading from too much velocity is posible but what about pressure? what kind of pressure can cast bullets actually take? if velocity is the main reason for low preasure then is it ok to load say a 190 grain bullet in the 7.62x39 at 40,000psi for a maximim volocity below the leading threshold? maybe even 250's in 30-30 an neer max preassure for a velocity below the typical leading velocity?