IRL a big part of hunting is selecting the right load for your kill. In game there are many rifles that are RATED up to a certain class, but have trouble delivering that killing power at the higher end of their available scale. Shotguns are a great example of this done right, with a variety of loads for different situations, while rifles just have the trade off of "do you want penetration, or expansion? Give us options on things like high velocity that has less drop and maintains power over distance, some ammo types that hit the middle ground between hollow points and polymer tips, give us VARIETY in our ammo selection