Jeeze. If all works out right, its 20 rounds minus 1 fouler, 4 shots to verify the accuracy and velocity of the cartridge, and 1 to shoot a deer. Well, I usually shoot some does for meat too, so 3 for deer.
So 12 laying around. Some years, I don't bother to load more and make do with half a box of last years loads. 12 minus 1, minus 4 leaves you at 7. For the hunt. That's kind of cutting it close!!!!
Seriously, I usually have gotten curious about some other bullet or powder and have went through a new development cycle and thus there are newly loaded stuff every year.
Had a buddies 270 shooting real nice with some Sierra slugs that became unobtainium. That gun we really stretched the limits. I think he last hunted with 4 rounds. Got some new slugs, but got lazy and have not yet worked up new recipe.
OP asked about hunting rifle. I don't hunt with my AR. Don't ask me about how many rounds I "used to have" for it.....