I've never shot a Deer with Buckshot but have shot a buttload of Fox with 00. To say I was underwhelmed would be an exaggeration, near useless would be closer to the truth. I figure if they won't reliably knock down a Fox I'm not going to try on a Deer.
I've used smoothbore Brenneke 2 3/4 slugs and they knocked down Hogs well at 35 yards or so, they'd probably get the job done at double that distance, but IMO iffy after 50 yards.
I hate wounding game and what is worse yet is wounding it and losing it forever. One reason is my personal hunting ethic, secondly is I spend a lot of time getting a decent shot at a decent Deer and darned if I'm going to waste a shot using inferior equipment.
Yes, I know many swear by Buckshot for Deer, though they rarely say how much tracking they had to do afterward or how many they have lost completely.