There’s been so much talk about balancing weapons by the devs but I believe there is something that could not only help balance out all weapons but also make some of the weaker guns like the .223, 6.5, etc more viable.
The ballistics rework would introduce a new stat to each round; stopping power (energy). This stat would indicate just how much energy the round carries. The higher it is, the more it staggers an animal upon impact. Now, this might not exactly be the most realistic way to go about it, but having the weaker rifles such as 6.5 and .223 have higher stopping power compared to the more powerful rifles like the .308 and .243 means that if you land a good shot, the animal would stay still for just a bit longer, allowing for the potential to land a follow up shot to make the animal bleed out faster. It could also help balance out the more powerful rifles, where an animal will flee almost immediately after being shot.
Along with this would be general rebalancing of different weapons, like making the .223 just generally more powerful and making the 6.5 a class 3-7 rifle. I feel this would make a lot of people happy.