Virtually any quality bullet from 240-300 grains you can get your hands on right now. I've used Speer, Sierra, Hornady, Nosler, Barnes, and Swift. You can spent way more than you need for deer inside of 50 yards. It does not take too much to kill one.
Ruger revolvers have long cylinders and handle heavy bullets well. If your bullet comes with two cannelures, load the longest that fits. You will need to work up loads for the longer C.O.A.L.
I've killed several with 240 and 300 grain XTPs. The 300s were my favorite for many years. This buck from the 1990's fell to 300 grain XTPs.The first one took out both lungs and exited. He went about 50 yards and he left a double blood trail in the snow from entrance and exit, with chunks of lung and froth.
He was down, but still alive and I put a finisher in him. I found the jackets from both bullets in the chest cavity.
View attachment 198030
(Boy was I young then!)
Then I got into casting boolits.
Today I use a cast Keith HP. An MP-Mold (MP 432-256 PB HP) copy of the Ideal 429421HP mold. I do not water drop. They drop at 245 grains and I lube with pure deer tallow. I load them over a hot charge of H110/W296. CCI Large Mag Pistol primer.
For my 45 Colt, I load the same MP mold in .454". Using the "penta" HP pin, they drop at 285 grains with WW alloy.
I've used Beartooth bullets and I have their book on fire-lapping. Their bullets are softer than hard cast and I like them.
I've lost one deer in the last 10 years and it was with Buffalo Bore WFNGC bullets out of a 45 Colt Blackhawk. 12 yards from a 17' tree stand.
She bolted after the shot. I came down and found one tuft of hair. Calm deer and a 12 shot from a rest. I knew it wasn't a miss. I spent the rest of the day looking for it.
I found the deer the next dry and tagged it. The bullet had penciled though and left no blood. The ground was frozen and she left no tracks.
In my opinion these loads are made to go nose to tail through a bear and don't do much if they don't hit bones. I should have used a neck shot.
This story to back up what
@howl said earlier. Driving hard cast as fast as you can make it go is not the answer.
Anyway -
That's my two bits.
Good luck. Handgunning for deer is a blast.