I think it would be a neat idea to try an implement a unique system of having a few different projectile grains available for the community voted calibers.
I will only give the one example: the .375 (from my research) has projectiles ranging from 200gr to 350/380gr. The 200gr could work for animal classes 5 - 7 while the 300+gr would be 7 - 9 or 8 - 9
I am not sure if it would be better to have 2 bullet types (High penetration & high expansion) per grain: 200gr polymer/round nose and 380gr polymer/round nose totaling 4 new ammos or if it should be just 2 rounds with above average stats. one 200gr round that can take 5 - 7 class animals effectively and on 380 that preforms similarly for 8 - 9 . Thereby only needing 2 new rounds.
This method would work similarly to the 7.62x54R and the 577/450 in that both of these rifles only have one ammo type, however, they both do incredibly well within their animal classifications (3 - 7 and 4 - 8 respectively)
Keep in mind this would also apply to the .300 and the .450 as well with their respective stats.
#Bullet grain varieties in community weapon pack.
compact pier