Originally Posted by
Big Z
JM,
I understand what you're saying. However, even if we elongated the copper bullet to retain the same mass it's BC suffers. Have you seen the Barnes MRX? It has a dense alloy in the rear of the bullet to give it additional penetration, and a higher BC compared to other plain-copper barnes bullets (it's expensive though
).
In the lighter for caliber bullets the copper bullets will have more potential for a higher BC. Take for example the ETip 150 grain with .469BC and 168 grain with .503BC. They are very long and sleek for their weight and have an advantage in Form Factor.
However as the bullets get heavier the copper bullets loose their advantage in form factor because they must be made to be stablilized in standard twist barrels and the bullet length must be limited. This results in a more rounded nose section in order to add mass in the length allowed in a given twist rate. The Form Factor suffers slightly from the relatively blunt nose.
The reason Barnes adds the dense material is to maintain the sleek nose section and still be within a length that can be stabilized. So in heavy bullets 200 - 240 grain 30 cal lead will actually have an advantage in BC potential.