Having the same S.D. does not mean that they will both penetrate exactly the same amount. And even if they did penetrate the same, if both bullets expand by the same percentage, the larger diameter bullet, will have a larger frontal area, which should produce a larger wound channel. If it really is as simple as having a high S.D. , why not just load up some 100gr .224" bullets for hunting Alaskan Brown bears?
