I shoot the 275 grain Parker Extreme out of rifles on the range and the accuracy was exceptional. I have yet to take a game animal with one. But from all the reports by different members on the lethality of the bullet I am sure it would do the job. Your reports on just the next size up only reinforced what I suspect to be true with the bullet.
You harvested a lot of venison. You will have a nice full winter of food. Congratulations.