I see more useful improvements in recent years with designs of bullets that make for better weight retention and controlled expansion than new cartridges making a difference. E.g. Nosler Accubond & Patition, Barnes X-Bullets, Hornady SST, others... Working with these and other outstanding bullets for accuracy, controlled damage to the game and types and loads of propellants, imo, will have a greater positive effect on hunting and rifle shooting sports than new cartridge configurations.