[Gene]

The energy that a powder charge delivers to the bullet is, fortunately, much greater than that delivered to the recoiling assembly -- although the momentum of the bullet is equal (but opposite) to that of the recoiling assembly. As the mass of the bullet decreases, slightly more energy is delivered to the bullet, and slightly less is delivered to the recoiling assembly.


For the same amount of recoil energy, either the powder charge must be increased, or a faster burning powder must be utilized. Both of these changes would indeed result in higher pressures. However, if the powder charge is the same as before, a more massive bullet can be expected to produce higher, not lower, pressure. (Imagine the extreme, limiting case, where the mass of the bullet is large enough to be considered a "plugged" barrel. Usually, the resulting pressure will cause a bulged or burst barrel!)


Regards,

Gene