I took my first deer with buckshot, but that was the last one.
Decades later I patterned my modest collection of shotguns with most of the buckshot available from #4 to 000. Three shotguns were tested: one had a 20" cylinder bore choke, another a 24" cylinder bore choke, and the last a 28" barrel with IC, mod, and full choke tubes.
Some worked better than others. As someone mentioned the Federal premium plated stuff worked well, and as someone else said the cylinder bore chokes did not work well. The result of this testing is that I wouldn't used any of the combinations for shooting deer beyond 20 yards. The admittedly arbitrary, but I believe reasonable, criterion I used was the ability to keep half the pellets on an 8-1/2" x 11" sheet of paper. None of them would do this at 25 yards.
FWIW, that first deer I shot with a Winchester model 1400 with a 28" barrel with a full choke tube using Remington 2-3/4" 12 pellet unplated and unbuffered 00. I shot two shots at the deer 35 yards away. Of the 24 pellets out there only one hit the deer. The pellet went between two ribs, through the valves of the heart, and out between two ribs. I have no idea where the other 23 pellets went
