You can neck it to 375. Some have tried necking it to 40 caliber. However at this point there is not enough shoulder to headspace. Of course these bigger bullets would eat up the powder capacity. Gotta go to the 45-70 for Cape Buffalo and T-Rex.. I could try the 405 Wichester for these big guys. Teddy R. loved the 405 in the 95 Lever action rifle and took all the African species with it. Of course now-a-days its much to small for these critters.